W78958B Datasheet, PDF (1/28 Pages) Winbond – 8-BIT EMULATION MICROCONTROLLER

W78958B
8-BIT EMULATION MICROCONTROLLER
GENERAL DESCRIPTION
The W78958B is an 8-bit emulation microcontroller that supports emulation for the Winbond W78C51
family of products, including the W78C31, W78C32, W78C51, W78C52, W78C154*, W78C58,
W78C438, and W78C458. It is designed to support real-time (up to 40 MHz) emulation tools, such as
in-circuit emulators (ICEs).
The W78958B is packaged in a 100-pin PQFP and is available in two different types, standard and
advanced. The standard type supports the functions of the W78C31, W78C32, W78C51, W78C52,
W78C154*, and W78C58. The advanced type supports the functions of the W78C438 and W78C458.
Both types can be operated in two modes, normal and emulation. In normal mode, the W78958B runs
freely, like the W78C51 family of products. In emulation mode, which is entered by driving the
ICESET pin high asynchronously, the W78958B stays in the S2 state of the next instruction. In this
mode, the W78958B allows direct access (read/write) to the special function registers (SFRs), the
program counter (PC), and the internal RAM. Also, it allows ICE makers to access the external
program and data memory easily, thereby eliminating the need for glue logic. Moreover, it provides
several signals to facilitate ICE design, including IPME (Internal Program Memory Enable), for
switching between "internal" and external ROM, ESEL (Emulation address space Select), for
combining the emulation program and data memory in a 128 KB SRAM, and CLKS1 (internal S1
state clock timing signal), for creating the emulation control signals. Once the ICESET pin goes low,
the W78958B will release its internal clock and return to its normal operating mode.
For detailed specifications concerning the W78C31, W78C32, W78C51, W78C52, W78C154*,
W78C58, W78C438, and W78C458, refer to the Functional Description below or to the Winbond
product specifications.
Notes for all W78C154*:
1. W78958B will emulate W78C154 except port1.6 & port1.7 as output mode:
W78958B port1.6 & port1.7 pull-ups
W78C154 port1.6 & port1.7 open drain
2. The specification of W78C154 is exclusive, therefore, the DC characteristics is not fully compatible with W78958B, however
the emulation function is still the same as W78958B.
1997
Publication Release Date: September
-1-
Revision A3