TangNano is driving 3.3V on pin 36 (WAIT_33)

[cristianoag]

The board lokks like is functioning adequately; however, there is a persistent issue with the Tang, consistently delivering 3.3V to pin 36. The transistor, intended to serve as a NOT gate for that line, is erroneously driving GND/0 to the Z80, consequently blocking the proper functioning of the MSX. I have attempted with two TangNano boards without success. Has anyone, aside from Felipe, successfully achieved compatibility with the latest PCB and code versions for this board?

[lfantoniosi]

what version are you using? there is a pullup resistor for this line (R4). The tang should put this line to GND. look this line:

assign wait_n = (ff_wait || ~reset_ram_n) ? 1'b1 : 1'b0;

is either 1 or 0. Previous versions of the fpga would put it to Z. You don't want it to be Z. So use the latest code available.

On Tue, Jan 2, 2024 at 12:53 PM Cristiano Goncalves < @.***> wrote:

The board lokks like is functioning adequately; however, there is a persistent issue with the Tang, consistently delivering 3.3V to pin 36. The transistor, intended to serve as a NOT gate for that line, is erroneously driving GND/0 to the Z80, consequently blocking the proper functioning of the MSX. I have attempted with two TangNano boards without success. Has anyone, aside from Felipe, successfully achieved compatibility with the latest PCB and code versions for this board?

— Reply to this email directly, view it on GitHub https://github.com/lfantoniosi/WonderTANG/issues/9, or unsubscribe https://github.com/notifications/unsubscribe-auth/ACCJWU6I7SMSL4FZMSOLWIDYMRXVZAVCNFSM6AAAAABBKRAS46VHI2DSMVQWIX3LMV43ASLTON2WKOZSGA3DEOJTGQ2DEMY . You are receiving this because you are subscribed to this thread.Message ID: @.***>

-- Luis Felipe Antoniosi

[lfantoniosi]

the wait line is an open collector and should remain GND at startup. So the transistor opens at the boot and closes forever after disconnecting the line

On Tue, Jan 2, 2024 at 2:05 PM Luis F. Antoniosi @.***> wrote:

what version are you using? there is a pullup resistor for this line (R4). The tang should put this line to GND. look this line:

assign wait_n = (ff_wait || ~reset_ram_n) ? 1'b1 : 1'b0;

is either 1 or 0. Previous versions of the fpga would put it to Z. You don't want it to be Z. So use the latest code available.

On Tue, Jan 2, 2024 at 12:53 PM Cristiano Goncalves < @.***> wrote:

The board lokks like is functioning adequately; however, there is a persistent issue with the Tang, consistently delivering 3.3V to pin 36. The transistor, intended to serve as a NOT gate for that line, is erroneously driving GND/0 to the Z80, consequently blocking the proper functioning of the MSX. I have attempted with two TangNano boards without success. Has anyone, aside from Felipe, successfully achieved compatibility with the latest PCB and code versions for this board?

— Reply to this email directly, view it on GitHub https://github.com/lfantoniosi/WonderTANG/issues/9, or unsubscribe https://github.com/notifications/unsubscribe-auth/ACCJWU6I7SMSL4FZMSOLWIDYMRXVZAVCNFSM6AAAAABBKRAS46VHI2DSMVQWIX3LMV43ASLTON2WKOZSGA3DEOJTGQ2DEMY . You are receiving this because you are subscribed to this thread.Message ID: @.***>

-- Luis Felipe Antoniosi

-- Luis Felipe Antoniosi

[cristianoag]

Problem was being caused by bad chips from AliExpress.