Datasheet

MCP2120
DS21618B-page 22 © 2007 Microchip Technology Inc.
FIGURE 4-8: TX and TXIR Waveforms
TABLE 4-8: TX AND TXIR REQUIREMENTS
AC Characteristics
Standard Operating Conditions (unless otherwise specified)
Operating Temperature –40°C ≤ T
A ≤ +85°C (industrial)
Operating Voltage VDD range is described in Section 4.1 “DC
Characteristics”
Param.
No.
Sym Characteristic Min Typ Max Units Conditions
IR100 TTXBIT Transmit Baud Rate Hardware Selection
768 — 768 T
OSC BAUD2:BAUD0 = 000
384 — 384 TOSC BAUD2:BAUD0 = 001
192 — 192 T
OSC BAUD2:BAUD0 = 010
128 — 128 T
OSC BAUD2:BAUD0 = 011
64 — 64 TOSC BAUD2:BAUD0 = 100
8 Software Selection
BAUD2:BAUD0 = 111
768 — 768 T
OSC Hex Command = 0x87
384 — 384 T
OSC Hex Command = 0x8B
192 — 192 T
OSC Hex Command = 0x85
128 — 128 T
OSC Hex Command = 0x83
64 — 64 T
OSC Hex Command = 0x81
IR120 T
TXL2TXIRH TX falling edge (↓) to
TXIR rising edge (↑)
(1)
7TBITCLK
- 8.34 µs
77T
BITCLK
+ 8.34 µs
TBITCLK
IR121 TTXIRPW TXIR pulse width 12 — 12 TOSC
IR122 TTXIRP TXIR bit period
(1)
—16—TBITCLK
Note 1: TBITCLK = TTXBIT/16
BITCLK
TX
TXIR
0100 01
IR100
IR121
IR120
Start Bit Data bit 7 Data bit 6 Data bit 5 Data bit ...
IR122 IR122 IR122 IR122 IR122 IR122