TTL Serial Adapter for C64/C128 UserPort.
The adapter is based on a non-inverting cmos buffer chip, CD4050. Following signals are used from the C64/C128:
FLAG <- RX (via a jumper)
PB0 <- RX
PB1 -> RTS
PB6 <- CTS
PA2 -> TX
There are also jumpers to switch signal path to enable null-modem communication. The default position is marked on pcb and it set for null-modem communication.
J4:
RX/TX
| o o | Null-Modem
| o o |
o o
RX/TX
o o Controller-Peripheral
| o o |
| o o |
J5:
CTS/RTS
| o o | Null-Modem
| o o |
o o
CTS/RTS
o o Controller-Peripheral
| o o |
| o o |
The serial output is pin compatible with common serial-usb adapters:
1 - GND
2 - CTS
3 - VCC
4 - TX
5 - RX
6 - DTR
Jumper 1 is used for enabeling RX interupt on the C64/C128. And jumper 2 is enabeling power thru the serial adapter.
J1:
RX Int
| o | RX interupt enabled
| o |
RX Int
o RX interupt disabled
o
J2:
Pwr
| o | Power feed from C64/C128 enabled
| o |
Pwr
o Power feed from C64/C128 disabled
o
Top side of pcb:
Bottom side of pcb, also containing info on jumper settings:
Case with pcb:
