| 摘要 |
When needing to make write accesses to both upper and lower sides of a counter in a timer, a CPU accesses the lower side last, and accesses the lower side first when needing to make read accesses thereto. The timer stores data of the data bus in the write buffer at the write access to the upper side, and writes the data of the data bus to the lower side and writes the data of the write buffer to the upper side at the write access to the lower side. At the read access to the lower side of the counter, the timer reads the data of the lower side for output to the data bus and reads the data of the upper side for storage in the read buffer. At the read access to the upper side, it outputs data of the read buffer to the data bus.
|
