MC94MX21 Technical Data, Rev. 1.
5
12
Freescale Semiconductor
Signal Descriptions
UART2_RXD
Receive Data input signal. This signal is multiplexed with KP_ROW6 signal from KPP.
UART2_TXD
Transmit Data output signal. This signal is multiplexed with KP_COL6 signal from KPP.
UART2_RTS
Request to Send input signal. This signal is multiplexed with KP_ROW7 signal from KPP.
UART2_CTS
Clear to Send output signal. This signal is multiplexed with KP_COL7 signal from KPP.
UART3_RXD
Receive Data input signal. This signal is multiplexed with IR_RXD from FIRI.
UART3_TXD
Transmit Data output signal. This signal is multiplexed with IR_TXD from FIRI.
UART3_RTS
Request to Send input signal
UART3_CTS
Clear to Send output signal
UART4_RXD
Receive Data input signal which is multiplexed with USBH1_RXDP and USBH1_TXDP.
UART4_TXD
Transmit Data output signal which is multiplexed with USBH1_TXDM.
UART4_RTS
Request to Send input signal which is multiplexed with USBH1_FS and USBH1_RXDP.
UART4_CTS
Clear to Send output signal which is multiplexed with USBH1_TXDP and USBH1_RXDM.
Serial Audio Port – SSI (configurable to I2S protocol and AC97)
SSI1_CLK
Serial clock signal which is output in master or input in slave
SSI1_TXD
Transmit serial data
SSI1_RXD
Receive serial data
SSI1_FS
Frame Sync signal which is output in master and input in slave
SYS_CLK1
SSI1 master clock. Multiplexed with TOUT.
SSI2_CLK
Serial clock signal which is output in master or input in slave.
SSI2_TXD
Transmit serial data signal
SSI2_RXD
Receive serial data
SSI2_FS
Frame Sync signal which is output in master and input in slave.
SYS_CLK2
SSI2 master clock. Multiplexed with TOUT.
SSI3_CLK
Serial clock signal which is output in master or input in slave. Multiplexed with SLCDC2_CLK
SSI3_TXD
Transmit serial data signal which is multiplexed with SLCDC2_CS
SSI3_RXD
Receive serial data which is multiplexed with SLCDC2_RS
SSI3_FS
Frame Sync signal which is output in master and input in slave. Multiplexed with SLCDC2_D0.
SAP_CLK
Serial clock signal which is output in master or input in slave.
SAP_TXD
Transmit serial data
SAP_RXD
Receive serial data
SAP_FS
Frame Sync signal which is output in master and input in slave.
I2C
I2C_CLK
I2C Clock
I2C_DATA
I2C Data
1-Wire
OWIRE
1-Wire input and output signal. This signal is multiplexed with JTAG RTCK.
Table 2. i.MX21 Signal Descriptions (Continued)
Signal Name
Function/Notes
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
MC94MX21DVKN3