Hardware Description
AT89C5131A Starter Kit Hardware User Guide
2-7
4245A–USB–11/04
2.4.3
TWI Peripheral
The CT3 and CT5 contacts have to be soldered in order to use the SDA and SCL alter-
nate P4.1 and P4.0 port configuration on the SPI connector (J4).
In order to use these signals on the J5 extension connector (SDA and SCL), the CT4
and CT6 contacts have to also be soldered.
2.4.4
SPI Peripheral
2.4.5
LED Controller
The AT89C5131A controller includes an LED controller on:
– P3.3 (LED 0)
– P3.5 (LED 1)
– P3.6 (LED 2)
– P3.7 (LED 3)
The on board LEDs can be controlled with the AT89C5131A if the corresponding con-
tacts CT9, CT10, CT11 and CT12 are bypassed.
Figure 2-6. On-board LEDs for LED Controller
0
1
LED
3
2
CT9
CT10
CT11
CT12
LED 0
LED 1
LED 2
LED 3
