ANROM/AN1ROM/BNROM '161 D-pins
Posted: Sun Jan 07, 2018 4:14 am
So I have been looking at these boards, ANROM/AN1ROM and BNROM and I see that the D pins on the '161's (pins 03 - 06) are wired a bit differently than on CN/UN-boards.
Here are how they are wired on the boards I have:
When I have looked at other board, it seems that unused D-pins are wired to +5V.
The BNROM connects '161 05 to PRG D2 and leaves '161 06 floating, while Q2/Q3 are floating.
The AN1ROM board connects unused '161 04 D1 to PRG D1 and '161 05 D2 to PRG D3 but leaves Q1 & Q2 floating.
So my question is, what difference does these connections make on the boards?
From what I understand is that the correct way is to connect unused D-pins to +5V, and not leave them floating, while Q-pins can be left floating, is this correct?
And what is the purpose to connect PRG D's to the '161 but leaving the Q's floating? Do they act like +5V on the '161?
Here are how they are wired on the boards I have:
Code: Select all
ANROM:
.---\/---.
+5V - |01 16| - +5V
/ROMSEL & '02 11 4B - |02 15| - NC
PRG D0 - |03 14| - PRG A15
PRG D1 - |04 13| - PRG A16
+5V - |05 12| - NC
PRG D4 - |06 11| - CIRAM A10
GND - |07 10| - GND
GND - |08 09| - CPU R/W & '02 03 1B/'02 02 1A
`--------'
'161
AN1ROM:
.---\/---.
+5V - |01 16| - +5V
/ROMSEL & '02 11 4B - |02 15| - NC
PRG D0 - |03 14| - PRG A15
PRG D1 - |04 13| - NC
PRG D3 - |05 12| - NC
PRG D4 - |06 11| - CIRAM A10
GND - |07 10| - GND
GND - |08 09| - CPU R/W & '02 03 1B/'02 02 1A
`--------'
'161
BNROM:
.---\/---.
+5V - |01 16| - +5V
/ROMSEL & PRG /CE - |02 15| - NC
PRG D0 - |03 14| - PRG A15
PRG D1 - |04 13| - PRG A16
PRG D2 - |05 12| - NC
NC - |06 11| - NC
GND - |07 10| - GND
GND - |08 09| - CPU R/W
`--------'
'161
The BNROM connects '161 05 to PRG D2 and leaves '161 06 floating, while Q2/Q3 are floating.
The AN1ROM board connects unused '161 04 D1 to PRG D1 and '161 05 D2 to PRG D3 but leaves Q1 & Q2 floating.
So my question is, what difference does these connections make on the boards?
From what I understand is that the correct way is to connect unused D-pins to +5V, and not leave them floating, while Q-pins can be left floating, is this correct?
And what is the purpose to connect PRG D's to the '161 but leaving the Q's floating? Do they act like +5V on the '161?