
HD404654 Series
4-Bit Single-Chip Microcomputer
Rev. 7.0
Sept. 1999
Description
The HD404654 Series is a member of the HMCS400-series of microcomputers designed to increase
program productivity with large-capacity memory. Each microcomputer has a high-precision dual-tone
multi-frequency (DTMF) generator, three timers, serial interface, voltage comparator, and input capture
circuit.
The HD404654 Series includes three chips: the HD404652 with 2 k-word ROM; the HD404654 with 4 k-
word ROM; and the HD4074654 with 4 k-word PROM (ZTAT
version).
The HD4074654 is a PROM version (ZTAT
microcomputer). A program can be written to the PROM by
a PROM writer, which can dramatically shorten system development periods and smooth the process from
debugging to mass production. (The ZTAT
version is 27256-compatible.)
ZTAT
: Zero Turn Around Time. ZTAT is a trademark of Hitachi Ltd.
Features
27 I/O pins and 5 dedicated input pins
10 high-current output pins: Six 15-mA sinks and four 10-mA sources
Three timer/counters
Eight-bit input capture circuit
Two timer outputs (including two PWM outputs)
One event counter input (including one double-edge function)
One clock-synchronous 8-bit serial interface
Voltage comparator (2 channels)
On-chip DTMF generator (f
OSC
= 400 kHz, 800 kHz, 2 MHz, 3.58 MHz or 4 MHz)
Built-in oscillators
Main clock: Ceramic or crystal oscillator (an external clock is also possible)
Six interrupt sources
Two by external sources
Four by internal sources
Subroutine stack up to 16 levels, including interrupts