Werner S
2013-12-13 18:35:44 UTC
Hello!
I need help with my new N8VEM. While I had no trouble building it, I cannot
establish a serial connection.
After triple checking everything (e.g. successfully continuity testing the
whole board) I narrowed it down to the Z80 /IORQ line (Pin 20) not
strobing. /MREQ (Pin 19) is strobing, though.
I verified that my Z84C0006PEG CPU
(https://groups.google.com/forum/#!topic/n8vem/2_SBBQ3g45g) correctly
receives the 4 MHz clock on Pin 6 using my DSO.
The CPU is also addressing the ROM via M27C801 Pin 22 (Chip Enable).
Any help is greatly appreciated.
Pictures:
Loading Image...
Loading Image...
Please tell me if I should take photos of specific sections/parts.
Werner
I need help with my new N8VEM. While I had no trouble building it, I cannot
establish a serial connection.
After triple checking everything (e.g. successfully continuity testing the
whole board) I narrowed it down to the Z80 /IORQ line (Pin 20) not
strobing. /MREQ (Pin 19) is strobing, though.
I verified that my Z84C0006PEG CPU
(https://groups.google.com/forum/#!topic/n8vem/2_SBBQ3g45g) correctly
receives the 4 MHz clock on Pin 6 using my DSO.
The CPU is also addressing the ROM via M27C801 Pin 22 (Chip Enable).
Any help is greatly appreciated.
Pictures:
Loading Image...
Loading Image...
Please tell me if I should take photos of specific sections/parts.
Werner
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