W921E880A/W921C880
1. GENERAL DESCRIPTION
The W921E880A/W921C880 are 4-bit micro-processor fabricated by CMOS process. With a single
channel DTMF generator, an 8-bit D/A converter circuit, a built in four by one channel comparator
circuit and four multi-function timers. The excellent memory structure, 8K super EPROM in
W921E880A and 8K mask ROM in W921C880 for program code and 1536 x 4 bit RAM minimize the
need for external memory devices. The W921E880A/W921C880 provides good solution for
consumming application, especially for telecommunication design with few external components.
Using the serial transmit/receive function, the W921E880A/W921C880 can interface with the
Winbond LCD driver IC using the serial control circuit.
2. FEATURES
Memory
• ROM (Super EPROM): 8K × 10 bits
• RAM: 1536 × 4 bits
− 64 × 4 bit Special registers
− 16 × 4 bit Working registers
− 128 × 4 bit General registers
− 304 × 4 bit Multi-purpose registers4 bit serial buffer registers
− 512 × 4-bit × 2 banks
Dual-clock Operation
• Crystal or RC for the main system clock: RC up to 4 MHz
Crystal for 400 K, 800 K, 2 M, 3.58 M, 4 MHz
• Crystal for subsystem clock: 32.768 KHz
I/O Pins
• 32 bidirectional and individually controllable I/O lines:
− P0 Port: P0.0−P0.3 large drive current Pins
− P1 Port: P1.0−P1.3 large drive current Pins
− P2 Port: P2.0−P2.3 large sink current pins and open drain option
− P3 Port: P3.0−P3.3 multi-function I/O
− P4 Port: P4.0−P4.3 open drain and pull high resistor option, multi-function I/O
− P5 Port: P5.0−P5.3 multi-function I/O
− P6 Port: P6.0−P6.3 open drain and pull high resistor option, multi-function I/O
− P7 Port: P7.0−P7.3 large sink current pins and open drain option
• 32 bidirectional I/O lines:
− P8 Port: P8.0−P8.3 large drive current pins
− P9 Port: P9.0−P9.3 large sink current pins and open drain option
Publication Release Date: July 1999
-3-
Revision A3