SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
For transmission, a channel can be:
The following definitions explain the channel control options:
Enabled channel | A channel that can begin transmission by passing data from the data transmit registers (DXRs) to the transmit shift registers (XSRs). |
Masked channel | A channel that cannot complete transmission. The DX pin is held in the high impedance state; data cannot be shifted out on the DX pin. |
In systems where symmetric transmit and receive provides software benefits, this feature allows transmit channels to be disabled on a shared serial bus. A similar feature is not needed for reception because multiple receptions cannot cause serial bus contention. | |
Disabled channel | A channel that is not enabled. A disabled channel is also masked. |
Because no DXR-to-XSR copy occurs, the XRDY bit of SPCR2 is not set. Therefore, no DMA synchronization event (XEVT) is generated, and if the transmit interrupt mode depends on XRDY (XINTM = 00b in SPCR2), no interrupt is generated. | |
The XEMPTY bit of SPCR2 is not affected. | |
Unmasked channel | A channel that is not masked. Data in the XSRs is shifted out on the DX pin. |