isp1508a NXP Semiconductors, isp1508a Datasheet - Page 24

• Manufacturer Part Number: isp1508a
• Description: Isp1508a; Isp1508b Ulpi Hi-speed Universal Serial Bus Transceiver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Table 12.
Table 13.
ISP1508A_ISP1508B_1
Product data sheet
Signal
SE0
INT
Reserved
Signal
TXD
RXD
Reserved
INT
Reserved
Signal mapping for 3-pin serial mode
UART signal mapping
Maps to
DATA0
DATA1
DATA2
DATA3
DATA[7:4]
9.2.5 Transparent UART mode
Maps to
DATA2
DATA3
DATA[7:4]
In transparent UART mode, the ISP1508 functions as a voltage level shifter between the
following pins:
The USB transceiver is used to drive the UART transmitting signal on the DM line. The
rise time and fall time of the transmitting signal is determined by whether a full-speed or
low-speed transceiver is in use. It is recommended to use a low-speed transceiver if the
UART bit rate is below 921 kbit/s for better EMI performance. If the UART bit rate is equal
to or above 921 kbit/s, a full-speed transceiver can be used.
In transparent UART mode, data bus definitions change to that shown in
Transparent UART mode is entered by setting some register bits in ULPI registers. The
recommended sequence is:
1. Set the XCVRSELECT[1:0] bits in the Function Control register to 10b (low-speed) or
2. Set the DP_PULLDOWN and DM_PULLDOWN bits in the OTG Control register to
3. Set the TERMSELECT bit in the Function Control register to logic 0 (power-on default
4. Set the TXD_EN and RXD_EN bits in the Carkit Control register to logic 1. These two
5. Set the CARKIT_MODE bit in the Interface Control register to logic 1.
•
•
Direction
I
O
O
O
O
From pin DATA0 (V
From pin DP (2.7 V level) to pin DATA1 (V
01b (full-speed). This setting affects the rise time and the fall time of the UART
transmitting signal on the DM line.
logic 0.
value).
Remark: Mandatory when a full-speed driver is used and optional for a low-speed
driver.
bits must be set together in one TXCMD.
Remark: The CARKIT_MODE, TXD_EN and RXD_EN bits must be set to logic 1.
The sequence of setting these register bits is ignored.
Direction
I/O
O
O
Description
UART TXD signal that is routed to the DM pin
UART RXD signal that is routed from the DP pin
reserved; the ISP1508 will drive this pin to LOW in UART mode
active HIGH interrupt indication; will be asserted and latched whenever any
unmasked interrupt occurs
reserved; the ISP1508 will drive these pins to LOW
Rev. 01 — 14 August 2007
Description
transmit single-ended zero on DP and DM when TX_ENABLE is HIGH
receive single-ended zero from DP and DM when TX_ENABLE is LOW
active HIGH interrupt indication; will be asserted and latched whenever
any unmasked interrupt occurs
reserved; the ISP1508 will drive these pins to LOW
CC(I/O)
…continued
level) to pin DM (2.7 V level).
ISP1508A; ISP1508B
CC(I/O)
level).
ULPI HS USB transceiver
© NXP B.V. 2007. All rights reserved.
Table
13.
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