Port Box

Table of Contents

• 1. About
  • Scope
  • Compatibility
• 2. Equipment Required for Operation
  • Power Adapter
  • Pass Thru Cable
  • Controller Port Jumper Cables
    • Controller Port Extension cables
    • DE-9 Ribbon Cables
    • Hybrid Cable Option
  • SIO Cable
• 3. Connecting the Test Assembly
• 4. Using the CPS SuperSALT Software
  • Executive Menu
  • Menu Navigation
  • Performance Test
  • Extended Unit Test
  • Individual Tests
  • Change Test Opts
    • Option: Test
    • Option: Sequence
    • Option: Disp Time
    • Option: Show Test Group
  • Show Err Summary
• 5. SuperSALT Diagnostic Tests
  • 2-Way Clock Test
  • 6502 Test
  • ANTIC Stress Test
  • Bar Test
  • Color Bars
    • Color Verification and Adjustment
  • GTIA Diagnostics
    • GTIA Phase 1: PMG Motion & Playfield Interaction
    • GTIA Diag. Part 2 — PMG Collision Detection
    • GTIA Diag. Part 3 — PMG Priority Control
  • I/O Port Tests
    • Voltage Test
    • I/O Test Progress
    • Voltage Tests
  • OS ROM Checksum
  • RAM Test
    • Employed RAM Test Methods
  • Tone Test
  • Video Test
  • Xternal Audio Test
  • Joystick Test
  • Keyboard Test
  • Paddle Test
  • Maintenance Mode
  • Fatal System Errors
• 6. Diagnostic Reference
  • Voltage Test Limits
  • Baud Rate Error Decode
• 7. Troubleshooting
• 8. Revision History

1. About

This guide describes the installation and operation of the 8YoRetro Port Box when used with the Atari CPS SuperSALT diagnostic software. It covers connecting the CPS SuperSALT Test Assembly (also referred to as the “test assembly” or “port box”), configuring the hardware, running the diagnostic tests, and interpreting their results.

The Port Box test assembly is an external hardware interface used by the CPS SuperSALT diagnostic software to exercise the external interfaces of an Atari 8-bit computer. Installed between the console and associated test cables, it provides the hardware resources required for the software to generate, route, and monitor signals, allowing comprehensive verification of the system’s external I/O functionality. It allows the diagnostic software to actively drive and measure signals that would otherwise require external test equipment.

Scope

This guide assumes the test assembly is assembled, calibrated and verified and focuses on its practical operation. For detailed information about calibration, design and operation of the test assembly, refer to the Port Box Technical Reference Manual.

Compatibility

The 8YoRetro Port Box is fully compatible with Atari’s original CPS SuperSALT diagnostic software and, when used with that software, behaves like the original Atari test assembly.

An enhanced version of the diagnostic software is available to support additional capabilities. This software is fully compatible with both the original Atari CPS SuperSALT Test Assembly and the 8YoRetro Port Box, including test assemblies equipped with the optional 8YoRetro Error Display Board.

Additional features provided by the enhanced software include:

• Automatic detection of the Port Box and Error Display Board during startup
• Support for the 8YoRetro Error Display Board
• The Port Box Hi-Z operating mode, which prevents conflicts with the 2-Way Clock test

Unless otherwise noted, the procedures and screen images in this manual assume the enhanced diagnostic software is being used.

2. Equipment Required for Operation

These are the items you will need to put the Port Box to use.

Power Adapter

Pass Thru Cable

Controller Port Jumper Cables

Four 9-conductor female-female DE-9 controller port jumper cables are required to connect the Port Box to a console’s controller jacks for diagnostic testing. Atari had supplied these with their original device, but they are virtually unobtainable today. The most practical alternative is to combine the following readily available items.

Controller Port Extension cables

DE-9 Ribbon Cables

Hybrid Cable Option

Optionally, DE-9 crimp connectors can be added to the aforementioned IDC header to female DE-9 IDC cables to create a hybrid IDC-header and gender-changer cable.

SIO Cable

A 13-conductor SIO cable is required to connect the Port Box to a console for testing. These are still fairly common on the second-hand market if you don’t already have one.

3. Connecting the Test Assembly

Perform the following steps exactly as described below to connect the test assembly.

1. Using 9-conductor controller cables, connect the corresponding controller ports between the console and the test assembly as follows:
   • Console controller port 1 to test assembly port 1
   • Console controller port 2 to test assembly port 2
   • Console controller port 3 to test assembly port 3 (if equipped)
   • Console controller port 4 to test assembly port 4 (if equipped)
2. Connect the test assembly to the console serial port using a 13-conductor SIO cable.
3. Connect the power adapter to the console:
   • 400/800/1200XL:
     • Insert the barrel connector from the console power adapter to the A/C power pass-thru jack on the test assembly.
     • Insert one end of the A/C pass-thru jumper cable into the other A/C pass-thru jack on the test assembly.
     • Insert the other end of the A/C pass-thru jumper cable into the console’s power input jack.
   • All other models:
     • Connect the power adapter directly to the console as described in the Atari owner’s manual.
4. Set the tone switch to the setting appropriate for the UUT. 400/800 vs XL/XE.
5. Connect the display/television cable as per the Atari owner’s manual.
6. Insert the SuperSALT diagnostic software cartridge.
7. Set the console power on – the splash screen should appear on the display (See figure 3-1).

During startup, the splash screen indicates the presence of supported hardware:

• SSA — SuperSALT Assembly
• EDB — Error Display Board

When hardware is present, these indicators cycle through the Atari color palette. If no indicators are shown, no test assembly or Error Display Board has been detected.

4. Using the CPS SuperSALT Software

The diagnostic software contained in SuperSALT is designed to test all areas of the system: MPU, RAM, ROM, SIO port, controller ports, ANTIC, GTIA, POKEY and keyboard, as well as video and audio logic.

The software provides three distinct test facilities, a sub menu where test parameters can be customized, and an error summary report. These are all accessible from the Executive Menu.

Executive Menu

The Executive Menu lies at the topmost navigation level. It provides access to the five primary diagnostic tools offered by the diagnostic software.

As shown in figure 4-1, the Executive Menu also displays the detected console family and installed RAM, along with on-screen prompts identifying the keys used to navigate the menu.

Menu Navigation

Use OPTION to execute the highlighted menu item, SELECT to move the highlight to the next item, and BREAK to return to the previous menu.

The Individual Tests, Change Test Opts, and Show Err Summary menus use different execution controls than the other test menus. Always refer to the instructions displayed at the bottom of the screen before proceeding.

During testing, pressing BREAK returns to the previous menu. Some tests must complete before the software responds to the BREAK key, so a brief delay is normal.

Performance Test

This is the default selection when SuperSALT starts and serves as the recommended starting point when evaluating a system of unknown condition. It executes a predefined sequence of tests designed to identify hardware faults in the console (see figure 4-2). The tests are listed on the screen and performed in the order displayed.

Note: Entering the Performance Test menu automatically resets the SEQUENCE and TEST GROUP options to their default values even if the test is not started. The DISP TIME and TEST:CONTINUOUS/SNGL PASS options are unaffected.

Extended Unit Test

This function executes a sequence of tests (see figure 4-3) that can be customized using the Change Test Opts menu. It is particularly useful for repeatedly exercising selected system functions when investigating intermittent faults.

This menu is static and does not reflect the current settings established through Change Test Opts. Nevertheless, the diagnostic tests execute according to the active test configuration.

Individual Tests

This menu provides direct access to individual tests, allowing each test to be selected and executed with a single keystroke (see figure 4-4). All tests operate according to the parameters configured in the Change Test Opts menu.

Change Test Opts

This menu provides additional control over the diagnostic test parameters (see figure 4-5). It is most commonly used with the Extended Unit Test to tailor individual tests or test sequences for troubleshooting, targeted functional verification, or long-duration burn-in testing.

Option: Test

Applies to: Extended Test • Performance Test • Individual Test

SNGL PASS	Terminates after one complete test cycle
CONTINUOUS	Repeats continuously until interrupted

Option: Sequence

Applies to: Extended Test

INCR	Runs tests in the defined order
RANDOM	Shuffles the test order before each cycle and repeats until interrupted

Option: Disp Time

Applies to: Extended Test • Performance Test • Individual Test

02–14	Delay (in seconds) after each test
RTN	Requires user input to continue at certain points

Option: Show Test Group

Applies to: Extended Test

This utility is used to define a custom test sequence (see figure 4-6) for the Extended Unit Test. A test group (also referred to as a test sequence) specifies both which tests are executed and the order in which they are executed.

The upper portion of the screen displays a list of available tests, each identified by a unique character shown as the first character of each entry. The current test sequence is shown near the bottom of the screen beside CURRENT SEQ as a string of these characters (for example, 26ABCGIORTVX), with each character corresponding to a test in the list.

To define or modify the sequence, enter the desired string of characters at the CURRENT SEQ prompt. The prompt accepts a valid test sequence character, or the following input:

DELETE	Removes the sequence character to the left of the cursor
RETURN	Accepts the sequence and returns to the Executive Menu
BREAK	Sets the sequence to 26ABCGIORTVX, and returns to the Executive Menu

Notes:

• The test sequence prompt provides only basic editing capability. Removing a test from the sequence may require deleting multiple characters and re-entering the remaining sequence.
• Twelve unique tests are available, but the test sequence prompt allows up to fourteen entries. Duplicate entries are permitted. The Error Summary counts each complete run of the test sequence as a single cycle, regardless of how many tests it contains; therefore, including duplicate entries may produce misleading statistical results.
• Unless the SEQUENCE option is set to RANDOM, the Extended Unit Test executes the test sequence from left to right.
• Entering the Performance Test resets the SEQUENCE option to its default INCR setting, and the Test Group to its default (26ABCGIORTVX).
• Submitting a null sequence reverts Test Group to its default (26ABCGIORTVX).

Show Err Summary

The error summary displays results and error codes accumulated since the software was last initialized, providing a concise overview for identifying the causes of failure. The System Error Summary Screen shown in figure 4-7 is the first of nine summary pages and displays cumulative error totals from the detail pages that follow, including the total number of errors and test cycles, as well as the number of errors listed in each page.

Note: The following tests are not represented in the Error Summary. Their results must be verified by the operator while the test is in progress.

• I/O Voltage Test
• ANTIC Stress Test
• 2-Way Clock Test
• Xternal Audio Test
• Bar Test
• Color Bars Test
• Tone Test
• Video Test

Note: The following diagnostic utilities require direct operator interaction and not represented in the Error Summary.

• Keyboard
• Joystick
• Paddle
• Maintenance Mode

5. SuperSALT Diagnostic Tests

This section describes each SuperSALT diagnostic test, including its purpose, operation, and any special requirements or observations needed to interpret the results. Where applicable, the test’s relationship to the automated test sequences and Error Summary is also discussed.

2-Way Clock Test

The 2-Way Clock test verifies operation of the serial port’s bidirectional clock line, referred to by the diagnostic software as the 2-Way Clock. The POKEY I.C. outputs a short 8-note melody on this line, which the port box routes to the console serial port’s audio input. As indicated in figure 5-1, hearing the melody through the A/V monitor or TV confirms that the console is capable of driving the 2-Way Clock line.

Troubleshooting: If the melody is faint or not heard, verify the port box tone switch position, all port box and A/V cable connections, and the TV/monitor volume before troubleshooting the console. These conditions are the most common causes of this symptom.

6502 Test

The 6502 Test verifies CPU operation by executing all 151 operation codes. Each cycle represents one complete execution of the instruction set, and each test pass consists of 100 cycles. Figure 5-2 shows the accumulated cycle and error counts displayed after each completed test pass.

Troubleshooting: A detected error may result from faulty low-memory RAM rather than the CPU. Run the RAM Test to verify memory operation before replacing the 6502. A severe CPU or related hardware fault may prevent the test from completing and cause the console to lock up.

ANTIC Stress Test

The ANTIC Stress Test verifies operation of the ANTIC I.C. by exercising the full range of ANTIC display modes. As shown in the animated display in figure 5-3, the operator determines whether the test passes by confirming that the display behaves as shown. Color is not significant; only the correct appearance and operation of each display element is required.

Bar Test

The Bar Test verifies that the GTIA I.C. is correctly generating the four luminance (LUM0-LUM3) bits by displaying an eight-step grayscale pattern. As shown in figure 5-4, the display consists of eight uniformly shaded horizontal bars progressing from black to white, with a thin white line immediately above the top bar. The operator determines whether the test passes by confirming that the display matches the figure.

Troubleshooting: Observe the display for at least 10 seconds to ensure that the bars remain steady and free of color. Missing bars, repeated or uneven shades, colored bars, or a display that shifts or flashes indicate a problem with the GTIA I.C. or its associated circuitry.

Color Bars

The Color Test verifies operation of the GTIA I.C.’s color generation circuitry and provides a means of adjusting the console’s color frequency. As shown in figure 5-5, the display consists of a 15-color rainbow scale separated from a single reference color bar by a gray reference bar. The operator determines whether the test passes by confirming that the upper and lower reference color bars are identical.

Color Verification and Adjustment

1. Allow the console to warm up for at least 15 minutes.
2. Compare the color bar immediately above the gray reference bar with the single color bar below it.
3. If necessary, adjust the GTIA color potentiometer until the two bars are identical.
4. Verify that each color bar is uniform across its entire width. Minor edge glitches are acceptable.

Troubleshooting: If the colors cannot be matched or the display contains missing bars or little to no color, verify the color adjustment before suspecting a faulty GTIA or ANTIC I.C. An incorrect or defective color crystal (Y1) may also produce incorrect colors.

GTIA Diagnostics

The GTIA Diagnostics test comprehensively exercises the GTIA I.C. by verifying Player/Missile Graphics (PMG), playfield priority, and collision-detection functions. The test is performed in three phases, shown in figures 5-6 through 5-8. While the software automatically verifies and tabulates collision-detection failures, the operator must observe each phase to confirm that the graphics appear and behave as described.

GTIA Phase 1: PMG Motion & Playfield Interaction

As shown in figure 5-6, four horizontal playfields labeled PLAYFIELD ZERO through THREE span the screen while groups of player- and missile-generated rectangles move between them. This phase verifies player and missile sizing, movement through the playfields, and collision detection between players and missiles.

GTIA Diag. Part 2 — PMG Collision Detection

Figure 5-7 shows two groups of rotating vertical bars. The narrow bars represent missiles, while the wide bars represent players. This phase continues to verify player and missile movement while exercising collision detection in the absence of playfield graphics.

GTIA Diag. Part 3 — PMG Priority Control

Figure 5-8 verifies GTIA priority control by displaying the words UNDER and OVER intersected by vertical bars. The words describe the position of the vertical bars relative to the text. Accordingly, the bars should appear behind the word UNDER and in front of the word OVER. The text window at the bottom of the screen identifies the player, missile, and playfield combinations currently being exercised.

Troubleshooting: Missing or malformed graphics, incorrect player or missile sizing, improper movement, incorrect priority relationships, or reported collision failures indicate a problem with the GTIA I.C. or its associated circuitry.

I/O Port Tests

The I/O Port Test verifies operation of the controller and serial I/O interfaces. A properly connected and operational port box is required to perform the following subtests::

• Voltage Verification: Verifies the +5 V and ground lines on each I/O port.
• Controller Port Data Lines: Verifies bidirectional operation of the controller port data lines.
• Trigger Lines: Verifies operation of the trigger inputs on each controller port.
• Potentiometer Lines: Verifies operation of the potentiometer inputs on each controller port.
• Serial Interface: Verifies the serial motor control, command, interrupt, data input, and data output lines.
• Serial Communications: Verifies asynchronous and synchronous serial communications over the full range of supported baud rates.

Voltage Test

Because the Voltage Test is not tabulated by the CPS SuperSALT software, the operator must determine the pass/fail condition by observing the real-time test results displayed on-screen. The Voltage Test screen (figures 5-9 through 5-11) displays the measured voltages applicable to the console under test. Measurements within the acceptable limits are displayed in green, while measurements outside those limits are displayed in red. The corresponding voltage limits are provided in table 6-1 for reference.

VI+ and VI- apply only to the Atari 400, 800, and 1200XL, where they represent the positive and negative outputs of the current-to-voltage converter. These values do not indicate current directly, but rather the converter output voltage, which is calibrated to a nominal value of 2.50 for a healthy, unmodified Atari 800 (48K) operating at idle. /stack

When testing other console configurations, modest deviations from the 2.50 baseline are normal and may result from hardware upgrades, modifications, or memory configuration. However, large deviations or significant differences between VI+ and VI- may indicate abnormal current consumption.

Enhanced Software: On XL/XE consoles, the software normally omits the VI+, VI-, and +12 V measurements because those signals are not present. However, the enhanced software automatically performs these tests whenever it detects voltages above a predefined threshold, allowing modified systems such as a 1200XL configured to emulate an 800XL to be tested correctly.

Troubleshooting: If all or most voltage measurements fail, first verify that the port box is properly connected, powered, and configured before troubleshooting the console. After correcting any setup problems, rerun the I/O Port Test.

Important: When using the original Atari diagnostic software, the Error Display must be disabled. Otherwise, the Voltage Test will report errors.

I/O Test Progress

Following the Voltage Test, the I/O Test Progress screen (figure 5-12) displays each remaining I/O subtest as it is executed. Test names are shown in white while pending and change to green upon completion, regardless of whether the subtest passes or fails. Any failures detected during these tests are recorded by the software and can later be reviewed using the Error Summary.

Voltage Tests

OS ROM Checksum

RAM Test

Employed RAM Test Methods

Tone Test

Video Test

Xternal Audio Test

Joystick Test

Keyboard Test

Paddle Test

Maintenance Mode

Fatal System Errors

6. Diagnostic Reference

Voltage Test Limits

Table 6-1 lists the acceptable voltage limits for each measurement displayed during the I/O Ports Voltage Test.

Baud Rate Error Decode

7. Troubleshooting

8. Revision History