
AMD Geode SC1200/SC1201 Processor Data Book
441
Electrical Specifications
Revision 7.1
9.3.11
Serial Port (UART)
Figure 9-42. UART, Sharp-IR, SIR, and Consumer Remote Control Timing Diagram
Table 9-32. UART, Sharp-IR, SIR, and Consumer Remote Control Timing Parameters
Symbol
Parameter
Min
Max
Unit
Comments
tBT
Single bit time in UART and
Sharp-IR
tBTN - 25
(Note 1)
tBTN + 25
ns
Transmitter
tBTN - 2%
tBTN + 2%
ns
Receiver
tCMW
Modulation signal pulse width in
Sharp-IR and Consumer
Remote Control
tCWN - 25
(Note 2)
tCWN + 25
ns
Transmitter
500
ns
Receiver
tCMP
Modulation signal period in
Sharp-IR and Consumer
Remote Control
tCPN - 25
(Note 3)
tCPN + 25
ns
Transmitter
tMMIN
(Note 4)
tMMAX
ns
Receiver
tSPW
SIR signal pulse width
(3/16) x tBTN - 15
(3/16) x tBTN + 15
ns
Transmitter, Variable
1.48
1.78
s
Transmitter, Fixed
1
s
Receiver
SDRT
SIR data rate tolerance % of
nominal data rate
± 0.87%
Transmitter
± 2.0%
Receiver
tSJT
SIR leading edge jitter % of
nominal bit duration
± 2.5%
Transmitter
± 6.5%
Receiver
Note 1. tBTN is the nominal bit time in UART, Sharp-IR, SIR and Consumer Remote Control modes. It is determined by the
setting of the Baud Generator Divisor registers.
Note 2. tCWN is the nominal pulse width of the modulation signal for Sharp-IR and Consumer Remote Control modes. It is
determined by the MCPW field (bits [7:5]) of the IRTXMC register and the TXHSC bit (bit 2) of the RCCFG register.
Note 3. tCPN is the nominal period of the modulation signal for Sharp-IR and Consumer Remote Control modes. It is deter-
mined by the MCFR field (bits [4:0]) of the IRTXMC registerand the TXHSC bit (bit 2) of the RCCFG register.
Note 4. tMMIN and tMMAX define the time range within which the period of the incoming subcarrier signal has to fall in order
for the signal to be accepted by the receiver. These time values are determined by the contents of register IRRXDC
and the setting of the RXHSC bit (bit 5) of the RCCFG register.
tBT
tSPW
tCMP
UART
Sharp IR
Consumer
Remote
SIR
tCMW
Control