Fujitsu FR81S User Manual
CHAPTER 39: RAMECC
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : RAMECC
FUJITSU SEMICONDUCTOR CONFIDENTIAL
22
5.3. Test Mode
The test mode is explained.
In this mode an ECC false error (a pseudo ECC error) is generated in order to debug software.
The ECC false error (a pseudo ECC error) of XBS RAM, as well as Backup-RAM, is generated in
accordance with the following procedures:
1. The address where a false error (a pseudo error) is caused in ECC false error generation address
register (EFEARX) is specified.
2. The byte and the bit are set by ECC false error generation control register XBS RAM (EFECRX).
(a) Byte position of EFECRX:EY[7:0] in which a false error (a pseudo error) is caused is specified.
(b) Bit position of EFECRX:EI[7:0] in which a false error (a pseudo error) is caused is specified.
3. One ("1") is written to the FERR bit of the ECC false error generation control register XBS RAM
(EFECRX).
Those data including errors intentionally are written to the address specified with EFEARX, where byte
position and bit position in the address are specified with EY[7:0] and EI[7:0], respectively. Then the CPU
reads the data subsequently, detecting the false error (a pseudo ECC error).
The operation after "1" is written to the FERR bit will be performed automatically.
MB91520 Series
MN705-00010-1v0-E
1313