Quote:
Can you give me additional references of the right GPIO to use and where to find it.
http://empegbbs.com/files/242954-serial-small.jpg
Sorry, had to push the compression really high and the resolution low to get it to upload to the BBS system.
GPIO23 is on pin 55 of the StrongArm. The top highlighted StrongArm pin on the photo is pin 53 (pin 1 is above the blue dot and they are numbered anticlockwise so pin 52 is the left-most pin on the top row, followed by 53 as the top-most pin on the left, pin 104: bottom-most pin on the left, pin 105: left-most pin on the bottom, pin 156: right-most pin on the bottom, pin 157: bottom-most pin on the right, and and finally pin 208: top-most pin on the right-hand row) [SA1100 datasheet, page 355 & 356].
From there, the signal goes to the MAX3241 (RS-232 transceiver chip) pin 13 and comes out on pin 10 [page 13 of the MAX3241 datasheet], then on to the 4420P-601 resistor array pin 13 and out on pin 8 [Bourns 4400P-series datasheet] and finally out on pin 4 of the on-board serial (D socket) connector.
However, you don't actually need to know this - you can just solder a wire to the back of the D socket. I'd strongly suggest working on getting the software working before doing anything to the hardware. You could simply plug a D plug into the socket temporarily while testing.
Many thanks to RobS for helping me figure out how this works, a few weeks ago.
Edited by mdavey (09/12/2004 13:50)
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