Electrical Specifications
5.16 UART Timing
Table 5–37 to Table 5–38 assume testing over recommended operating conditions (see Figure 5–35).
Table 5–37. UART Timing Requirements
MIN
tw(UDB)R
Pulse width, receive data bit
tw(USB)R
Pulse width, receive start bit
† U = UART baud time = 1/programmed baud rate
0.99U†
0.99U†
MAX
1.01U†
1.01U†
UNIT
ns
ns
Table 5–38. UART Switching Characteristics
PARAMETER
fbaud
tw(UDB)X
Maximum programmable baud rate
Pulse width, transmit data bit
U – 2†
U – 2†
MIN
MAX
5
U + 2†
U + 2†
UNIT
MHz
ns
ns
tw(USB)X
Pulse width, transmit start bit
† U = UART baud time = 1/programmed baud rate
tw(USB)X
Data Bits
TX
Start
Bit
tw(UDB)X
Data Bits
RX
Start
Bit
tw(UDB)R
tw(USB)R
Figure 5–35. UART Timings
November 2001 – Revised July 2003
SPRS007B
95
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