COP8AME9_14 Datasheet, PDF (26/102 Pages) Texas Instruments – COP8AME9 8-Bit CMOS Flash Microcontroller with 8k Memory, Dual Op Amps, Virtual EEPROM, Temperature Sensor, 10-Bit A/D and Brownout Reset

COP8AME9, COP8ANE9
SNOS930F – MARCH 2001 – REVISED MARCH 2013
In-System Programming
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INTRODUCTION
This device provides the capability to program the program memory while installed in an application board. This
feature is called In System Programming (ISP). It provides a means of ISP by using the MICROWIRE/PLUS, or
the user can provide his own, customized ISP routine. The factory installed ISP uses the MICROWIRE/PLUS
port. The user can provide his own ISP routine that uses any of the capabilities of the device, such as USART,
parallel port, etc.
FUNCTIONAL DESCRIPTION
The organization of the ISP feature consists of the user flash program memory, the factory boot ROM, and some
registers dedicated to performing the ISP function. See Figure 14 for a simplified block diagram. The factory
installed ISP that uses MICROWIRE/PLUS is located in the Boot ROM. The size of the Boot ROM is 1K bytes
and also contains code to facilitate in system emulation capability. If a user chooses to write his own ISP routine,
it must be located in the flash program memory.
Figure 14. Block Diagram of ISP
As described in OPTION REGISTER, there is a bit, FLEX, that controls whether the device exits RESET
executing from the flash memory or the Boot ROM. The user must program the FLEX bit as appropriate for the
application. In the erased state, the FLEX bit = 0 and the device will power-up executing from Boot ROM. When
FLEX = 0, this assumes that either the MICROWIRE/PLUS ISP routine or external programming is being used to
program the device. If using the MICROWIRE/PLUS ISP routine, the software in the boot ROM will monitor the
MICROWIRE/PLUS for commands to program the flash memory. When programming the flash program memory
is complete, the FLEX bit will have to be programmed to a 1 and the device will have to be reset, either by
pulling external Reset to ground or by a MICROWIRE/PLUS ISP EXIT command, before execution from flash
program memory will occur.
If FLEX = 1, upon exiting Reset, the device will begin executing from location 0000 in the flash program memory.
The assumption, here, is that either the application is not using ISP, is using MICROWIRE/PLUS ISP by jumping
to it within the application code, or is using a customized ISP routine. If a customized ISP routine is being used,
then it must be programmed into the flash memory by means of the MICROWIRE/PLUS ISP or external
programming as described in the preceding paragraph.
REGISTERS
There are six registers required to support ISP: Address Register Hi byte (ISPADHI), Address Register Low byte
(ISPADLO), Read Data Register (ISPRD), Write Data Register (ISPWR), Write Timing Register (PGMTIM), and
the Control Register (ISPCNTRL). The ISPCNTRL Register is not available to the user.
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