AMD SC3200 manual Single bit time in Uart, Transmitter, Sharp-IR, Modulation signal period

32581C Electrical Specifications

9.3.10Serial Port (UART)

Table 9-29. UART, Sharp-IR, SIR, and Consumer Remote Control Timing Parameters

Symbol	Parameter	Min	Max	Unit	Comments
tBT	Single bit time in UART and	tBTN - 25	tBTN + 25	ns	Transmitter
	Sharp-IR	(Note 1)
		tBTN - 2%	tBTN + 2%	ns	Receiver
tCMW	Modulation signal pulse width in	tCWN - 25	tCWN + 25	ns	Transmitter
	Sharp-IR and Consumer	(Note 2)
	Remote Control
		500		ns	Receiver
tCMP	Modulation signal period in	tCPN - 25	tCPN + 25	ns	Transmitter
	Sharp-IR and Consumer	(Note 3)
	Remote Control
		tMMIN	tMMAX	ns	Receiver
		(Note 4)	(Note 4)
tSPW	SIR signal pulse width	(3/16) x tBTN - 15	(3/16) x tBTN + 15	ns	Transmitter, Variable
		(Note 1)	(Note 1)
		1.48	1.78	µs	Transmitter, Fixed
		1		µs	Receiver
SDRT	SIR data rate tolerance % of		± 0.87%		Transmitter
	nominal data rate
			± 2.0%		Receiver
tSJT	SIR leading edge jitter % of		± 2.5%		Transmitter
	nominal bit duration
			± 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

UART

tCMP

Sharp IR tCMW

Consumer

Remote

Control

tSPW

SIR

Figure 9-41. UART, Sharp-IR, SIR, and Consumer Remote Control Timing Diagram

404 AMD Geode™ SC3200 Processor Data Book