The Sharp PC-1600 has a serial device built in. It uses fairly standard 5V logic, and can be interfaced with currently available FTDI adapters. When using an original (non-cloned) FTDI adapter, no additional logic chips or inverters are required.
These are the components that I used:
- 1mm pins, bent 90 degrees
- A small board for soldering the pins. Search for "1.27mm 2.54mm Adapter Board" on the merchant site of your choice. While I found no 15 pin boards, 12 pins are enough for the signals that are required.
- USB/UART cable, I used this one: "FTDI TTL-232R-5V-WE", i.e. 5V logic and wire ends.
Before the USB / UART adapter can be used, it needs to be reprogrammed using a Windows machine. The signals of the RX, TX, RTS and CTS pins need to be inverted. This can be done with a utility provided by FTDI, and is not covered here. This is a one time operation, because the change is persistent even after unplugging the cable.
The wiring is as follows (pin 1 is the rightmost pin of the PC-1600's 15-pin serial connector):
| Pin | Signal PC-1600 | Connect this cable of the USB/UART | USB/UART wire color |
|---|---|---|---|
| 2 | TX | RX | yellow |
| 3 | RX | TX | orange |
| 4 | RTS | CTS | brown |
| 5 | CTS | RTS | green |
| 7 | Ground | Ground | black |
Note: Do not connect the red cable (5V) of the adapter. I simply cut the cable off.
RTS and CTS (pins 4 and 5) are required: sde put --device pc1600 uses RTS/CTS
hardware flow control by default. If they are missing, swapped or not inverted, the
transfer hangs (the PC-1600 waits in LOAD, sde reports that the PC-1600 never
raised CTS). A cable without these lines still works with sde put --no-flowcontrol,
which paces the transfer instead.
On macOS, use the built-in driver; don't install FTDI's own VCP driver, which handles flow control worse for this use.
For how the macOS and Linux drivers handle this adapter's flow control (RTS/CTS, XON/XOFF), errors and limits, see SerialDriverAnalysis.md.
Note that I had to trim the edges of the board, because it would not have fit otherwise:
The PC-1500 does not have a serial port built in. There was an add-on from Sharp
called "CE-158" which provided a serial and a parallel port. Its serial port is
RS-232 only, so connecting it needs a USB serial adapter with RS-232 levels. Even then
the original CE-158 is not supported: it would most likely need a lower baud rate than
the 19200 baud sde uses for the PC-1500, and sde has no option to set one.
Jeff Birt built a modern equivalent of this add-on,
and sells it under the name
CE-158X.
sde is tested with the USB port (U1) of the CE-158X.