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2) Target devices of bug
Target devices of this bug is as following.
Series Devices
MB90480/485series MB90F481, MB90F482, MB90V480, MB90486, MB90487,
MB90487A, MB90488A, MB90F488, MB90V485
Table 2. Target devices of bug
3) Countermeasure and revising schedule
For this bug, Fujitsu consider that provisional countermeasure is possible by
following method.
3-1) Provisional countermeasure plan with combination between uDMA and UART
(Synchronization/Asynchronization) transmission (Software countermeasure)
At using EI2OS of secret function for MB90480/485series, the behavior of bug
is avoided. EI2OS has same function as uDMA, and same data transmission as
uDMA is possible. However note that execution time of transmission between
EI2OS and uDMA is different.
With using uDMA With using EI
2
OS
IOA updated / fixed
selection
Fixed Updated Fixed Updated
Fixed 17 19 32 34
BAP updated
/ fixed
selection
Updated 19 21 34 36
Table 3. Execution time of transmission (Unit: Machine clock cycle)
3-2) Permanent countermeasure with combination between uDMA and UART
(Synchronization/Asynchronization) transmission (Hardware revision)
For countermeasure of bug with combination between uDMA and UART
(Synchronization/Asynchronization) transmission, Fujitsu revise MB90485series
as high priority. Revision schedule of MB90485series is as following. Also
countermeasure device of this bug is added “B” suffix to end of part number.
Part number after
revision
Providing schedule
MB90486B (MASK)
2004/08/M: from
reception
MB90487B (MASK)
2004/08/M: from
reception
MB90488B (MASK)
2004/08/M: from
reception
MB90F488B (FLASH)
2004/08/12: provide
ES
MB90V485B (EVA)
2004/08/13: provide
ES
Table 4. Part number after revision and schedule