W78C438C_06 Datasheet, PDF (2/22 Pages) Winbond – 8-BIT MICROCONTROLLER

W78C438C
1. GENERAL DESCRIPTION
The W78C438C is a high-performance single-chip CMOS 8-bit microcontroller that is a derivative of
the W78C58 microcontroller family. The W78C438C is functionally compatible with the W78C32,
except that it provides either a 64 KB program/1 MB data memory address or memory-mapped chip
select logic, five general I/O ports, and four external interrupts.
In the W78C32, two I/O ports, Port 1 and Port 3, are available for general-purpose use (Port 3 also
supports alternative functions), and Port 2 and Port 0 are used as the address bus and data bus,
respectively. To enable Port 0 and Port 2 to also be used as general purpose I/O ports, the
W78C438C provides two dedicated address ports (AP5 and AP6) that serve as address output for 64
KB of memory and one address/data port (DP4) that serves as ROM code input and external RAM
data input/output. Unlike the W78C32, this product does not require an external latch device for
multiplexing low byte addresses. The W78C438C also provides four pins (AP7.0−AP7.3) to support
either 64 KB program/1 MB data memory space or memory-mapped chip select logic, one parallel I/O
port (Port 8) without bit addressing mode, and two additional external interrupts ( INT2 , INT3 ) .
The W78C438C is programmed in a manner fully compatible with that used to program the W78C32,
except that the external data RAM is accessed by the "MOVX @Ri" instruction. Address paging is
performed by loading page addresses into the HB (high byte) register, which is not a standard register
in the W78C32, before execution of the "MOVX @Ri" instruction.
2. FEATURES
y 8-bit CMOS microcontroller
y Fully static design
y DC to 40 MHz operation
y ROM-less operation
y 256-byte on-chip scratchpad RAM
y Either 64 KB program/1 MB data memory address space or 4 memory-mapped chip select pins
y One 8-bit data/address port
y Two 8-bit and one 4-bit (optional) address ports
y Five 8-bit bidirectional I/O ports
− Four 8-bit bit-addressable I/O ports and one 8-bit parallel I/O port
y Eight-source, two-level interrupt capability
y Three 16-bit timer/counters
y Four external interrupts
y One full-duplex serial channel
y Built-in power management
− Idle mode
− Power-down mode
y Packages:
− Lead Free (RoHS) PLCC 84: W78C438C40PL
− Lead Free (RoHS) PQFP 100: W78C438C40FL
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