User`s manual

User’s Manual 37
APPENDIX D. PROGRAMMING CABLE
This appendix provides technical information about the Rabbit
2000 microprocessor when connecting the RabbitLink and a PC
via a programming cable.
The programming cable has two connectors, labeled DIAG and PROG . The programming
cable connects the PC’s COM port to the programming port, which is header J8, on the
RabbitLink. The programming port pin assignments are shown in Figure D-1.
Figure D-1. Programming Port Pin Assignments
The PROG Connector
The PROG connector is used to download firmware to the RabbitLink (see Section 3.2.1,
"Downloading Firmware to the RabbitLink"). Using the PROG connector to plug the pro-
gramming cable into the programming port results in pulling the Rabbit 2000 SMODE
lines high. This causes the Rabbit to enter cold boot mode after a reset. The reset occurs
when the RFU opens the serial port of the PC with the DTR line high, then changes it to
low. This pulses the reset line on the RabbitLink.
In cold boot mode the processor runs a small program contained in an internal ROM. This
program receives triplets sent by the PC. It is through this mechanism that the RFU sends
firmware to the RabbitLink. Please see the Rabbit 2000 Designer’s Handbook for a detailed
description of triplets and the cold boot mode.
10
12
34
56
78
9
PROGRAMMING PORT PIN ASSIGNMENTS
(Rabbit PQFP pins are shown in parenthesis)
1. RXA (51)
2. GND
3. CKLKA (94)
4. +5 V/+3 V
5. /RESET
6. TXA (54)
7. n.c.
8. STATUS (output) (38)
9. SMODE0 (36)
10. SMODE1 (35)
~50 kW
GND
~50 kW
+
~50 kW
GND
~50 kW
+
~10 kW
+
Programming Port
Pin Numbers