September 24, 1998

EDN's 25th Annual Microprocessor/Microcontroller Directory

Texas Instruments TMS370
	View block diagram

The TMS370's register-based architecture has 73 instructions and as many as 256 8-bit registers in a RAM register file. The CPU can address these registers as registers or as RAM. An 8-bit stack pointer references the processor stack, which resides in the register RAM. The CPU also contains a 16-bit program counter to access as much as 64 kbytes and an 8-bit program-status register. You access on-chip peripherals and EEPROM/ EPROM programming control through a set of memory-mapped registers in a peripheral file. The TMS370 assigns each peripheral a frame of 16 registers in the 16-frame peripheral file.

Although the TMS370 has an 8-bit ALU, the chip handles 16-bit operations, including arithmetic, load/stores, and memory/register and memory/memory exchanges.

Power management: Standby mode stops the internal clock in every module except the Timer 1 module, which brings the CPU out of standby. Halt stops the internal clock, which you can restart by a reset or an external interrupt. Both modes maintain RAM. You can program and selectively turn off most special peripherals.

Special instructions: The TMS370's bit-manipulation instructions are set, clear, complement, and jump if bit is 0 or 1. Bit instructions operate on registers in register or peripheral files. Math functions include add, subtract, increment, decrement, decimal adjust, multiply, and divide. The CPU has some 16-bit operations, such as word moves (a register pair) and incrementing a word, and it uses 16-bit offsets for jumps and register pairs as an address for subroutine calls.

Special on-chip peripherals: The TMS370 timers provide multiple options. For example, Timer 1 supports 16 bits of granularity with an 8-bit prescaler and includes a watchdog. Timers 1 and 2 both automatically generate PWM. The TMS370x3x family includes the Programmable Acquisition and Control Timer (PACT), a timer coprocessor module that generates as many as eight PWMs without CPU overhead. The 370's serial communications and serial peripheral interfaces both have selectable baud rates and data formats.

Development tools: TI's development tools for the TMS370 offer support from evaluation through production. All tools use a similar interface that allows symbolic debugging in either assembly language or C source code. A $99 starter kit includes a software simulator, an assembler/linker, and a board for programming EPROM-based µCs. TI's C compiler accepts ANSI C source code and performs four selectable levels of generic and target-specific optimizations. The $1000 TMS370 Compact Development Tool (CDT) supports all 135 TMS370 family members with the same development platform. This single-board, real-time, in-circuit emulator plugs into your PC. Through the use of an appropriate target cable, the CDT can connect to the application board's microcontroller socket and emulate the proper TMS370 devices. Features include program-counter trace, an integrated EPROM/EEPROM programmer, an assembler/linker, and a symbolic debugger.

Second sources: There are no second sources for the TMS370.

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