C511_1 Datasheet, PDF (111/128 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

EEPROM Programming Interface
SAB-C513A-H
9.2.5 EEPROM Access Operations
Three different operations are provided for programming and verifying the EEPROM memory
contents:
- Erase (delete, clear) memory content(s)
- Write (program) memory content(s)
- Read memory content.
All operations are byte oriented, however, for deleting and writing the memory more than one byte
can be selected (see PMSEL register description). This allows quick erasure of memory blocks or
the complete memory as well as efficient testing of the memory. Read operations only will operate
on single bytes.
9.2.5.1 Erase Operation
The erase operation clears the total EEPROM memory or a selected area of it to an initial state. In
this initial state all memory locations have a FFH as content. As in an EPROM, a program operation
can only write a “0” to a bit of an EEPROM cell, not vice versa. Therefore, before programming of
the EEPROM, the bytes to be programmed should be erased.
At the erase operation the following steps must be executed:
1. Selection of the memory area (block or single byte) to be erased by programming PMSEL.
2. Writing the address of the byte/block to be cleared into PADRH and PADRL.
3. Set EEPROM operation mode bits in PCNTRL to EOM2-0=001B and the PROG bit to 1.
4. Wait at least 10 ms.
5. Reset the PROG bit to 0 with still EOM2-0=001B.
6. Wait 20 µs (guard time for discharging high voltage generator).
7. Set EOM2-0=000B and PROG=0.
The steps of the erase operation are illustrated in figure 9-9-6.
Figure 9-6
Erase Sequence
After erasing a memory byte contains FFH.
Semiconductor Group
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