W921E400A Datasheet, PDF (3/53 Pages) Winbond – 4-BIT MICROCONTROLLER

W921E400A/W921C400
1. GENERAL DESCRIPTION
The W921E400A/W921C400 is a single-chip CMOS 4-bit microcontroller that is a subset of
W921E880A/W921C880. It features a 4-bit ALU, three multi-function timers, one channel DTMF
generator, a beep tone generator, a serial I/O port and built in four by one channel comparator circuit,
thus it can be easily implemented as telephone processor. Using the serial transmit/receive function,
the W921E400A/W921C400 series can interface with Winbond LCD driver IC by the serial control
circuit. There are also seven interrupt sources and 48-level subroutine nesting for interrupt
applications.
The W921E400A/W921C400 have two power reduction modes, hold mode and stop mode, which
help to minimize power dissipation. This product is a powerful microcontroller for telephone
processor, remote controllers, multiple I/O products, keyboard controllers, speech synthesis LSI
controllers, and other products with few components.
2. FEATURES
Operating Voltage
• 2.8 to 5.5V operating voltage for W921E400A EPROM TYPE
• 2.4 to 5.5V operating voltage for W921C400 MASK ROM TYPE
Operating Frequency
• Crystal or RC for main system clock:
− Crystal for 400K, 800K, 2M, 3.58M, 4 MHz
− RC up to 4 MHz
Memory
• 4K × 10-bit ROM (super EPROM):
• 512 × 4-bit RAM:
− 64 × 4-bit special register
− 16 × 4-bit working register
− 128 × 4-bit general register
− 304 × 4-bit multi-purpose register
Stack
• 8-bit stack pointer
I/O Pins
• 13 bidirectional and individually controllable I/O lines:
− P2 Port: P2.0 to P2.1 large sink current pins and open drain option
− P3 Port: P3.0 to P3.3 multi-function I/O
− P4 Port: P4.2 to P4.3 open drain and pull high resistor option, multi-function I/O
− P5 Port: P5.1 multi-function I/O
− P6 Port: P6.0 to P6.3 open drain and pull high resistor option, multi-function I/O
• 8 bidirectional I/O lines:
− PA Port: PA.0 to PA.3 open drain and pull high resistor option
− PB Port: PB.0 to PB.3 open drain and pull high resistor option
Publication Release Date: July 1999
-3-
Revision A3