Hardware Description
AT89STK-06 Demo Board User Guide
2-5
4339B–CAN–11/04
2.4
Serial Interfaces
2.4.1
RS-232C
All CAN microcontrollers have one on-chip UART peripheral. Only the asynchronous
mode is supported by the AT89STK-06 board.
The AT89STK-06 board is supplied with a RS-232 driver/receiver. Only one female DB9
connector assumes the RS-232 connections. A full range of configuration can be set
with two Rx lines and two Tx lines.
Figure 2-4 . RS-232 DB9 Connections
Figure 2-5 . Typical PC Connection Lay-out
Figure 2-6. RS-232 DB9
1
RS-232 DB9 front view
pin 2
5
6
9
2
3
4
7
8
RS-TxD
pin 3
RS-RxD
pin 4
pin 6
pin 5
Gnd
pin 7
RS-CTS
pin 8
RS-RTS
AT89C51CC0x / RS-232 DB9
PC / DB9 serial port
Pin Nb
(
COM1 or COMx
)
Function
Pin Nb
Function
2
TxD
(AT89C51CC0x)
5
Gnd
2
3
RxD
(PC)
TxD
(PC)
3
RxD
(AT89C51CC0x)
5
Gnd
Green Rx LED
Red Tx LED
“Auto_ISP”
Jumpers
