Rainbow Electronics T89C5121 - Manual (Page 2)

2
A/T8xC5121
4164G–SCR–07/06
Description
T8xC5121 is a high performance CMOS ROM/CRAM derivative of the 80C51 CMOS
single chip 8-bit microcontrollers.
T8xC5121 retains the features of the Atmel 80C51 with extended ROM capacity (16
Kbytes), 512 bytes of internal RAM, a 4-level interrupt system, two 16-bit timer/counters
(T0/T1), a full duplex enhanced UART (EUART) with baud rate generator (BRG) and an
on-chip oscillator.
In addition, the T8xC5121 have, a Multi protocol Smart Card Interface, a dual data
pointer, 2 programmable LED current sources (2-4-10 mA) and a hardware Watchdog.
T89C5121 Flash RAM version and T85C5121 Code RAM version can be loaded by In-
System Programming (ISP) software residing in the on-chip ROM from a low-cost exter-
nal serial EEPROM or from R232 interface.
T8xC5121 have 2 software-selectable modes of reduced activity for further reduction in
power consumption.
Block Diagram
Figure 1. Block Diagram
Notes: 1. Alternate function of Port 1
2. Alternate function of Port 3
3. Only for the Code RAM version
4. Only for PLCC52
Timer 0 INT
RAM
256 x8
T0 T1
Rx
D
Tx
D
XTAL2
XTAL1
EUART
CPU
Timer 1
INT
1
Ctrl
INT
0
C51
CORE
(2) (2) (2) (2)
P1
IB-bus
RS
T
VS
S
V
CC
(1):
ROM
Xtal
Osc
XRAM
256
x8
SCIB
CC8
CRST
CPRES
CIO
CC4
CCLK
C V
CC
6 I/Os
LI
CRST1
CIO1
CCLK1
(2)
(2)
(2)
(4)
16K x8
CRAM
16K x8
(2) (2)
P3
8 I/Os
D
V
CC
Voltage
Reg.
(1)
(1)
(1)
(1)
(1)
(1)
LED
Drive
Direct
LE
D
0
LE
D
1
(2) (2)
Output
:1-16
Clock
(3)
Prescaler
X2
Watchdog
E
V
CC
CV
S
S
P2 P0
EA
PSEN
ALE
DC/DC
Converter
Level
Shifters
POR
PFD
Alternate
Card
BRG
Parallel I/O Ports