Texas Instruments MSC1210 manual Hardware Configuration Memory

Hardware Configuration

15.1.2 Hardware Configuration Memory

In addition to the hardware configuration registers, 116 bytes of configuration memory are available to you for your own use. This configuration memory, also set during device programming, can hold information such as unique serial numbers, parameters, or any other information that you want to record. The configuration information is available to the program when the part is operating for read operations, but cannot be changed.

Setting the configuration memory is accomplished in the same way as setting the hardware configuration registers as described above—the only difference is that the configuration memory available is located from 8002H through 806FH. Thus, the first five bytes of your configuration memory could be set with assembly code such as the following:

CSEG AT 8002H	;Address of user configuration memory
DB 10h,20h,30h,40h,50h	;User configuration data, up to 116 bytes

Be careful that the configuration data is located at 8002H and includes no more than 116 bytes of data. Including more than 116 bytes of configuration data causes the data to spill over into the area of configuration memory that is used to configure the actual MSC1210 hardware.

15.1.3 Accessing Configuration Memory in a User Program

The 128 bytes of flash configuration memory, which include the 116 bytes of user-defined configuration data and two bytes of hardware configuration regis- ters, can be read by your program in normal operation. However, the configu- ration data is not obtained by reading the code address to which they were pro- grammed. That is to say, although flash configuration memory is set at pro- gram time by placing it at code memory addresses 8002H through 806FH (user configuration memory) and 807EH and 807FH (hardware configuration), the data cannot be read by reading the data from that program memory address. Rather, two SFRs are used to read the configuration memory.

In code, your program may set the configuration address register SFR, CADDR (93H), to the address of the byte of configuration memory that should be read. The address must be a value between 00H and 7FH reflecting the 128 bytes of configuration flash memory. Once the address is set in CADDR, the value of that address can then be read by reading the CDATA (94H) SFR.

Note:

You may not write to the CADDR SFR if the code is executing from flash memory. This is because that would imply that the MSC1210 fetch the flash configuration memory at the same time as it is fetching instructions from flash memory.

To read flash configuration memory, a call must be made to the 2k Boot ROM that is included on the MSC1210. A call to the faddr_data_read function, pass- ing it the address as a parameter, will return the value of the configuration memory address.

Advanced Topics 15-5