W921C840
Description
The W921E840A/W921C840 is single-chip CMOS 4-bit microcontroller that is subset of W921E880A/W921C880. They features four multi-function timers, one channel DTMF generator, an 8-bit D/A converter circuit, ten interrupt sources, 48-level subroutine nesting, and built in four by one channel comparator circuit.
Key Features
- FEATURES Operating Voltage
- 2.8 to 5.5V operating voltage for W921E840A EPROM Type
- 2.4 to 5.5V operating voltage for W921C840 Mask ROM Type Operating Frequency
- Crystal or RC for main system clock - Crystal for 400 K, 800 K, 2 M, 3.58 M, 4 MHz - RC up to 4 MHz Memory
- 8K × 10-bit ROM (super EPROM)
- 512 × 4-bit RAM - 64 × 4-bit special registers - 16 × 4-bit working registers - 128 × 4-bit general registers - 304 × 4-bit multi-purpose registers Stack
- 8-bit stack pointer I/O Pins
- 20 bidirectional and individually controllable I/O lines - P2 Port: P2.0 to P2.3 large sink current pins and open drain option - P3 Port: P3.0 to P3.3 multi-function I/O - P4 Port: P4.0 to P4.3 open drain and pull high resistor option, multi-function I/O - P5 Port: P5.0 to P5.3 multi-function I/O - P6 Port: P6.0 to P6.3 open drain and pull high resistor option, multi-function I/O
- 14 bidirectional I/O lines - PA Port: PA.0 to PA.3 open drain and pull high resistor option Publication Release Date: July 1999 -3- Revision A3
