14.3.9 Digital Loopback Mode
The I2C module support a self-test mode called digital loopback, which is enabled by setting the DLB bit in the
I2CMDR register. In this mode, data transmitted out of the I2CDXR register is received in the I2CDRR register.
The data follows an internal path, and takes n cycles to reach I2CDRR, where:
n = 8 * (SYSCLK) / (I2C module clock (Fmod))
The transmit clock and the receive clock are the same. The address seen on the external SDA pin is the address
in the I2COAR register.
shows the signal routing in digital loopback mode.
I2CDRR
I2CRSR
0
1
I2CSAR
I2COAR
0
1
I2CDXR
I2CXSR
0
1
0
0
DLB
SCL_IN
SCL_OUT
Address/data
To internal I
2
C logic
From internal I
2
C logic
To internal
I2
C logic
To CPU
From CPU
From CPU
From CPU
SCL
SDA
I
2
C module
DLB
DLB
Figure 14-16. Pin Diagram Showing the Effects of the Digital Loopback Mode (DLB) Bit
Note
The free data format (I2CMDR.FDF = 1) is not supported in digital loopback mode.
Inter-Integrated Circuit Module (I2C)
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
849
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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