CMS32L051 User Manual |Chapter 12 Universal Serial Communication Unit
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12.9.5 Calculation of the transfer rate
Simplified I
2
C (IIC00, IIC01, IIC10, IIC11, IIC20, IIC21) The transmission rate of communication can be
calculated using the following calculation formula.
Notice Setting SDRmn[15:9] to 0000000B is prohibited, and the SDRmn [15:9] must be greater than or equal to
0000001B. The duty cycle of the SCL signal output by the simple I2C is 50%. In the I2 C-bus specification, the
low width of the SCL signal is greater than the high level width. Therefore, if set to 400kbps in fast mode or 1Mbps
in enhanced fast mode, the low level width of the SCL signal output is less than I2C The specification value of the
bus. SDRmn[15:9] must be given a value that meets the I2 C-bus specification.
Note 1 Because the value of SDRmn[15:9] is the value of bit15~9 of the serial data register (SDRmn)
(0000001B~1111111B). ), so 1 to 127.
2. m: Unit number (m=0, 1) n: channel number (n=0~3) mn=00~03 , 10~11.
The operating clock (f
MCK
) depends on the serial clock select register m (SPSm) and bit 15 (CKSmn bit) of
the serial mode register mn (SMRmn).
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