Z-World EG2110, User Manual

Page: 35 / 50

User’s Manual 31
A
PPENDIX
D. P
ROGRAMMING
C
ABLE
This appendix provides technical information about the Rabbit 2000
™
microprocessor when con-
necting 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, "Down-
loading Firmware to the RabbitLink"). Using the
PROG
connector to plug the programming 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.
The DIAG Connector
The
DIAG
connector is used to configure network parameters for the RabbitLink. It is also used to
treat the programming port as a regular serial port; because the programming cable contains an
active circuit board that converts RS-232 voltage levels used by the PC serial port to CMOS volt-
age levels used by the Rabbit, the
DIAG
connector allows the programming cable to be used as an
RS-232 to CMOS level converter for serial communication.
The /RESET line and the SMODE1 and SMODE0 pins are not present in the
DIAG
connector.
10
1 2
3 4
5 6
7 8
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 k W
GND
~50 k W
+
~50 k W
GND
~50 k W
+
~10 k W
+
Programming Port
Pin Numbers