MOTOROLA Chapter 19. Serial Communications Controllers (SCCs) 19-19

Part IV. Communications Processor Module

Figure 19-10. Output Delay from CTS Asserted for Synchronous Protocols

If CTS is programmed to envelope data, negating it during frame transmission causes aCTS lost error. Negating CTS forces RTS high and Tx data to become idle. IfGSMR_H[CTSS] is zero, the SCC must sample CTS before a CTS lost is recognized;otherwise, the negation of CTS immediately causes the CTS lost condition. SeeFigure 19-11.
1. GSMR_H[CTSS] = 0. CTSP is a donÕt care.
TCLK
TXD
Last Bit of Frame DataFirst Bit of Frame Data
NOTE:
CTS Sampled Low Here
1. GSMR_H[CTSS] = 1. CTSP is a donÕt care.
TCLK
TXD
Last Bit of Frame DataFirst Bit of Frame Data
NOTE:
(Output)
RTS
(Output)
CTS
(Input)
(Output)
RTS
(Output)
CTS
(Input)