Fujitsu FR81S User Manual
CHAPTER 50: RAM DIAGNOSIS FUNCTION
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : RAM DIAGNOSIS FUNCTION
FUJITSU SEMICONDUCTOR CONFIDENTIAL
40
5.1. RAM Diagnosis
This section explains the RAM diagnosis.
XBS RAM diagnosis is performed only in the following order.
1. Unique (unique data is {Address [3:0],{6{Address [7:0]}}})
2. Checker
3. March (all "0" -> all "1" are executed in that order.)
The RAM diagnosis is performed following the settings in the TTYP[2:0] bits of the TEST diagnosis function
register (TTCRX). By default, unique and checker are executed.
The coverage of the RAM diagnosis for XBS RAM is specified by the TEST start address register
(TASARX) and TEST end address register (TAEARX).
Following procedure is required for RAM diagnosis for XBS RAM.
1. Before start diagnosing, read TRUN of the TEST diagnosis function register (TTCRX) and IRUN of
the TEST initialization function register (TICRX), and check that they are "0".
In the case where TTCRX.TRUN or TICRX,IRUN is not "0":
- Wait for TTCRX.TRUN="0", then clear TTCRX.TCI.
- Wait for TICRX.IRUN="0", then clear TICRX.ICI.
2. Write continuously "02
H
" -> "42
H
" -> "82
H
" -> "C2
H
" four times to the TEST key code control register
(TKCCRX), then start diagnosing.
When all RAM diagnosis types for XBS RAM are completed, TRUN bit of the TEST diagnosis function
register (TTCRX) becomes "0" to finish the RAM diagnosis. The results of the diagnosis is retained in the
TEST error address register 0 to 2 (TEAR0X to TEAR2X) and TEST diagnosis function register (TTCRX).
The RAM holds the diagnosis data.
In addition, write continuously "00
H
" -> "40
H
" -> "80
H
" -> "C0
H
" four times to the TEST key code control
register (TKCCRX) to terminate the RAM diagnosis for XBS RAM forcibly. RAM diagnosis ends even if it
is in progress. In this case, the diagnosis result is not reliable.
Perform the same procedure for RAM diagnosis for Backup RAM.
MB91520 Series
MN705-00010-1v0-E
2161