Serial Communications Controllers
MPC885 PowerQUICC Family Reference Manual, Rev. 2
21-18
Freescale Semiconductor
When RTS is asserted, if CTS is not already asserted, delays to the first data bit depend on when CTS is
asserted.
Figure 21-10
shows that the delay between CTS and the data can be approximately 0.5 to 1 bit
times or 0 bit times, depending on GSMR_H[CTSS].
Figure 21-10. Output Delay from CTS Asserted for Synchronous Protocols
If CTS is programmed to envelope data, negating it during frame transmission causes a CTS lost error.
Negating CTS forces RTS high and Tx data to become idle. If GSMR_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. See
Figure 21-11
.
1. GSMR_H[CTSS] = 0. CTSP is a don’t care.
TCLK
TXD
Last Bit of Frame Data
First Bit of Frame Data
NOTE:
CTS Sampled Low Here
1. GSMR_H[CTSS] = 1. CTSP is a don’t care.
TCLK
TXD
Last Bit of Frame Data
First Bit of Frame Data
NOTE:
(Output)
RTS
(Output)
CTS
(Input)
(Output)
RTS
(Output)
CTS
(Input)
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...