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Troubleshooting

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akuker edited this page May 23, 2021 · 46 revisions

Table of Contents

Hardware troubleshooting

Schematics for the RaSCSI are available here: https://github.com/akuker/RASCSI/raw/master/hw/rascsi_2p3/rascsi_2p3_sch.pdf

Termination

First step in troubleshooting is to check the termination. Seriously. Check this.

https://lowendmac.com/1998/termination-explained/

Check the Termination again

Re-check it again.

Loopback Testing

A way to check out the RaSCSI hardware is to create a loopback cable. This can be done using jumper wires or a specially-constructed DB25 male jack connector can be created to allow easy re-use.

The diagram for the loopback connections is shown here. This is when looking into the RaSCSI board connector (female connector)

Link to original drawing

Once you have the loopback connections made, you can checkout the RaSCSI source code and run the loopback test python script. (Note: This requires python3 to run)

Before running this test:

- Ensure that you have termination enabled before running this test!!

- Ensure that the RaSCSI service is NOT running `sudo systemctl stop rascsi` 

cd ~
git clone https://github.com/akuker/RASCSI.git
cd ~/RASCSI
# FOR NOW, the code is only available on the 'rascsi_checkout' branch
git checkout rascsi_checkout
cd ~/RASCSI/src/loopback_test/
./test.py

The Python test script will list all of the SCSI signals that are not working properly. You can the use the schematicto debug if there are any broken traces, lifted pads or bad solder joints.

Note: this concept was original created by Saybur for the Scuznet board: https://github.com/saybur/scuznet/tree/master/testing

Example Successful Test Run

Example Test Run With Failures

In this case, there is something wrong with either the "C/D" SCSI signal or the "D4" SCSI data line or both.

Multimeter Testing

You can test each individual SCSI signal using a multimeter. This procedure is listed here.

Turn on the termination DIP switches

Pull out your trusty multimeter. With the RaSCSI software running, disconnect all SCSI devices and check the voltages:

  • TPWR should be 5v
  • D0-D7 should be around 3.08v
  • Control signals should be around 3.08v
STOP the RaSCSI service `sudo systemctl stop rascsi`.
  • Check the LEDS
 raspi-gpio set 4 op dh #  ACT LED should be ON
 raspi-gpio set 4 op dl #  ACT LED should be OFF
 raspi-gpio set 5 op dh #  ENB LED should be ON
 raspi-gpio set 5 op dl #  ENB LED should be OFF
  • Set the direction of the transceivers to be outputs
 raspi-gpio set 8 op dl #PI-DTD is GPIO 8 - set LOW for Pi->SCSI output
 raspi-gpio set 6 op dh #PI-IND is GPIO 6 - set HIGH for Pi->SCSI output
 raspi-gpio set 7 op dh #PI-TAD is GPIO 7 - set HIGH for Pi-SCSI output
  • Check Data 0
 raspi-gpio set 10 op dh # D0 output should be around 3v
 raspi-gpio set 10 op dl # D0 output should be around 0v
  • Repeat for all of the other data and control signals
 raspi-gpio set <GPIO> op dh # <Signal> output should be around 3v
 raspi-gpio set <Signal> op dl # <Signal> output should be around 0v
Signal GPIO Direction Control Direction: Pi->SCSI Direction: SCSI->PI
D0 10 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
D1 11 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
D2 12 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
D3 13 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
D4 14 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
D5 15 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
D6 16 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
D7 17 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
DP 18 DTD (GPIO 8) raspi-gpio set 8 op dl raspi-gpio set 8 op dh
I/O 25 TAD (GPIO 7) raspi-gpio set 7 op dh raspi-gpio set 7 op dl
REQ 15 TAD (GPIO 7) raspi-gpio set 7 op dh raspi-gpio set 7 op dl
C/D 18 TAD (GPIO 7) raspi-gpio set 7 op dh raspi-gpio set 7 op dl
MSG 23 TAD (GPIO 7) raspi-gpio set 7 op dh raspi-gpio set 7 op dl
BSY 26 TAD (GPIO 7) raspi-gpio set 7 op dh raspi-gpio set 7 op dl
SEL 27 IND (GPIO 6) raspi-gpio set 6 op dh raspi-gpio set 6 op dl
RST 20 IND (GPIO 6) raspi-gpio set 6 op dh raspi-gpio set 6 op dl
ACK 21 IND (GPIO 6) raspi-gpio set 6 op dh raspi-gpio set 6 op dl
ATN 19 IND (GPIO 6) raspi-gpio set 6 op dh raspi-gpio set 6 op dl

Software

Duplicate ID

This is a known bug with the RaSCSI software. You can mitigate it by changing IDs around.

  • For example,
 ID 1 - RaSCSI-Boot.hda 
 ID 2 - DaynaPort SCSI/Link
  • would become
 ID 0 - RaSCSI-Boot.hda
 ID 1 - DaynaPort SCSI/Link

This bug will be fixed in a future update. I've seen the most success attaching the DaynaPort on ID 1, as ID 2 gave me the Duplicate ID error. This only seems to be happening with the DaynaPort device.

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