Design based on single-chip simulator (1)

Single chip microcomputer STM32L151CCU6

1206RGB (single)

0201 package SLP0603 ESD electrostatic diode 5V one-way ESD

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ) 7.5PF 10PPM 20PPM 30PPM

Photocoupler

SST89C54/58 (referred to as 89C54/58) is a multi-purpose 51 series MCU introduced by SST Company of the United States. It integrates 20kB/36 kB SuperFlashE ""PROM program memory, which is divided into BLOCK0 (16kB/32kB) and BLOCKl (4kB). ) Two pieces. Among them, BLOCKl can be mapped to the highest or lowest end of the 64kB storage space, and can be invisible to the program counter. Due to its unique advantages in memory structure, the 89C54/58 is very suitable for use as a microcontroller emulator.

2 SST89C54/58 program storage structure

2.1 Memory Structure

The memory block BLOCK0 in the 89C54/58 slice occupies the storage space from 0000H to 3FFFH/7FFFH, and BLOCK1 occupies the storage space from F000H to FFFFH. The 89C54/58 storage structure is shown in Figure 1.

When EA#=1, for the program counter, BLOCK0 is always visible for code access; BLOCKl code access is achieved through special function registers SFCM, SFCF, SFAL, SFAH, SFDT and SFST. . When SFCF[7]=1, BLOCKl is visible.

2.2 Memory Remapping (Re-mapping)

The memory remapping function of the 89C54/58 makes the system interrupt vector area still available when programming BLOCK0 (the normal 8051 series MCU does not have this feature). The 89C54/58 provides four memory remapping methods. The size of the memory remapping is controlled by MAP_ENCl:0). When MAP-

3 Design of SCM89C58 based MCU emulator

3.1 Introduction to Design Principles

The simulator circuit design is shown in Figure 2. In the figure, U2 is the serial communication interface chip MAX232, and U1 is 89C54/58. The monitoring program of 89C54/58 communicates with KEILC51 through the serial port of PC to realize real-time simulation function.

3.2 Adding the simulator monitor program

The 89C54/58 emulator monitoring program SoftlCE (Softwareln-CircuitEmulator) provided by SST can be loaded by BSL (Boot-StrapLoader) provided by SST or written by a third-party programmer supporting SST89C54/58.