NJU3505L 查看數據表（PDF） - Japan Radio Corporation

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产品描述 (功能)

比赛名单

NJU3505L

4-BIT SINGLE CHIP MICRO CONTROLLER

Japan Radio Corporation  

NJU3505

[ Reading data from 12-bit Timer Counter2 to RAM ]

Though the data of the Timer and Counter can be read in the count operation, the read data is

sometimes incorrect when the clock inputs to the counter during the reading operation.

When the 12-bit counter data is read in count operation as shown in the following timing chart(An

example of data reading from the counter to RAM), Timer often counts up between the first 4-bit data

reading and the second. In case of the following chart, though the timer data is "110h" when the

lower 4-bit data is gotten, it is "10Fh" when the higher 4-bit data is gotten. Therefore the final data

becomes to be "11Fh".

[ An example of data reading from 12-bit Timer Counter2 to RAM ]

Counter clock

Timer Data

(12bit)

10D

Reading

Y-register

LSB

RAM

(4bit Y-address=0)

RAM

(4bit Y-address=1)

RAM

10E

10F

E

0

1

110

F

1

1

111

112

1

1

1

10Eh

11Fh:Incorrect data

111h

There are some other cases to read the incorrect data from the 12-bit counter during the count operation

depending on the relation with the external clock speed and the system execution speed.

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