TMS370 MAJOR COMPONENTS ARCHITECTURE
1–8
POST OFFICE BOX 1443
HOUSTON, TEXAS 77251–1443
program memory (ROM/EPROM)
The program memory provides alternatives to meet the needs of different applications. The program memory
modules presently contain 2K, 4K, 8K, 16K, 24K,32K, or 48K bytes of memory. The program memory in
TMS370C6xx, SE370C6xx, TMS370C7xx, and SE370C7xx devices is EPROM. EPROM devices in a
windowed ceramic package can be programmed, erased, and reprogrammed for prototyping. EPROM devices
in a non-windowed plastic package are one-time programmable (OTP) devices that are used for small
production runs. In the TMS370C0xx, TMS370C3xx, and TMS370C4xx devices, the program memory is
mask-ROM that is programmed at the factory. ROM devices are appropriate for large-volume production.
input/output ports
The TMS370 family of devices has a varying number of I/O ports that have various port widths. Table 3 lists the
available I/O port widths, by the number of bits, for each of the TMS370 subfamilies.
Table 3. Bits Per Port for TMS370 Devices
SUBFAMILIES
BITS FOR PORTS A–H
C
A
B
D
G
H
’x0x, ’x1x
8
5
’x2x
8
8
1
5
’x32
8
4
’x36
8
5
’x4x
8
8
8
8
3
8
8
8
5
6
8
5
’x5x – (64 pins)
8
8
8
’x5x – (68 pins)
’x6x
’x7x – (64 pins)
8
8
8
6
6
’x7x – (68 pins)
8
8
8
8
6
’x8x – (40 pins)
8
8
6
5
’x8x – (44 pins)
8
8
8
5
’x9x
8
5
’xAx
8
8
1
5
’xBx – (64 pins)
8
8
8
6
8
1
’xBx – (68 pins)
8
8
8
8
8
1
’xCx
For all subfamilies, the ports for these microcontrollers can be programmed, bit by bit, to function as either digital
input or digital output.
These ports can be configured by the software as the data, control, and address buses for external memory. Any
bits not needed for external memory can be programmed to be either digital input or digital output.
8
4
timer 1
Timer 1 is a 16-bit timer that can be configured in the following ways:
A programmable 8-bit prescaler (provides a 24-bit real-time timer) that determines the independent clock
sources for the general-purpose timer and the watchdog (WD) timer
A 16-bit event timer to keep a cumulative total of the transitions
A 16-bit pulse accumulator to measure the pulse-input width
A 16-bit input-capture function that latches the counter value on the occurrence of an external input
Two 16-bit compare registers that trigger when the counter matches the contents of a compare register
A self-contained pulse-width modulated (PWM) output control function