CHAPTER 11 


HARDWARE REFERENCE 


Note: This document is a beta version and may be subject to change. 


About this chapter 


This chapter presents the details of some of the new hardware present in the Psion Series 3c and Siena 
machines. 


The 15-way SIBO/RS232 connector 


Four distinct types of signal are brought in/out via this connector: 
e RS232 level serial data and handshaking lines 
e Power in to provide operating power. 
e A SIBO serial channel at 3V logic levels, to provide an interface to ASIC4/5 based peripherals 
e 5V power out to power non self-powered peripherals. 


Not all of these signals are relevant to both machines; the split being: 


The board mounted connector is a Honda type with custom polarisation. The diagram below shows the 


pinout of this connector: 


11-1 


SIENA/SERIES 3C UPGRADE 


The pins on the connector have the following functions: 
Siena Vin at +6Vd.c., 10% — 
Series 3c 5V Power out, 30mA maximum. 
RTS (RS232) 
DTR (RS2372) 
TXD (RS232) 
DSR (RS232) 
DCD (RS232) 
CTS (RS232) 
RXD (RS2372) 


0 mn nNn nn fF W WN 


SDOE - SIBO data direction control. 


— 
o 


EXTSTAT - active low SIBO peripheral detect line. 


ee 
ee 


EXON - SIBO external turn-on 


= 
N 


INT - SIBO peripheral interrupt 


— 
Ww 


SD - SIBO serial data 


_ 
Ts 


SCK - SIBO data clock 


—- 
—s 
—> 
— 
a 
— 
— 
— 
— 
— 
+ 
ad 
—_—- 


= 
Nn 


GND - Signal and Power ground 


GND - Shield frame ground 


Key: Out of machine _, 
Into machine — 


Ground — 


e The SIBO lines on the Series 3c are not intended to be used for peripherals. They are present 
on the unit for test purposes only. 


e The SIBO lines on the Siena are intended for use with the external SSD drive only, and are 
filtered to match that peripheral. 


e It should be particularly noted that the SIBO lines on pins 9-14 on both machines are at 3V logic 
levels, as opposed to the 5V levels present on the Series 3a, and are unbuffered; that is, there is no 
SIBO data direction control imposed on the lines, as is present on the Series 3a external SIBO bus. 


e The contacts for pins | and 15 on the socket protrude slightly and make contact before the 
remaining pins on the connector. 


e The only difference between the Series 3c and the Siena pin-outs is the function of pin 1. Applying 
6V to this pin on the Series 3c will have no detrimental effect. The 5V output on the Series 3c is 
the normal VCC5 output provided on the SIBO expansion port of an Series 3a, less one Schottky 
diode drop. The VCCEXT output on Series 3c gets turned on two EPOC ticks after EXTSTAT 
goes low. 


e On the Siena, EXTSTAT directly controls the DNMI line, whilst on the Series 3c, it is polled on 
PBO6. 


e On the Series 3c, the DSR line performs an external wake-up of the machine through an internal 
connection to the EXON line. This does not happen on the Siena. 


11-2 


