C8051F124-GQR Datasheet, PDF (241/350 Pages) Silicon Laboratories – Mixed Signal ISP Flash MCU Family

C8051F120/1/2/3/4/5/6/7
C8051F130/1/2/3
18.1.6. External Memory Interface Pin Assignments
If the External Memory Interface (EMIF) is enabled on the Low ports (Ports 0 through 3), EMIFLE (XBR2.5)
should be set to a logic 1 so that the Crossbar will not assign peripherals to P0.7 (/WR), P0.6 (/RD), and if
the External Memory Interface is in Multiplexed mode, P0.5 (ALE). Figure 18.4 shows an example Cross-
bar Decode Table with EMIFLE=1 and the EMIF in Multiplexed mode. Figure 18.5 shows an example
Crossbar Decode Table with EMIFLE=1 and the EMIF in Non-multiplexed mode.
If the External Memory Interface is enabled on the Low ports and an off-chip MOVX operation occurs, the
External Memory Interface will control the output states of the affected Port pins during the execution
phase of the MOVX instruction, regardless of the settings of the Crossbar registers or the Port Data regis-
ters. The output configuration of the Port pins is not affected by the EMIF operation, except that Read
operations will explicitly disable the output drivers on the Data Bus. See Section “17. External Data Mem-
ory Interface and On-Chip XRAM” on page 219 for more information about the External Memory Inter-
face.
P0
P1
P2
P3
Crossbar Register Bits
PIN I/O 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
TX0
●
RX0
●
UART0EN: XBR0.2
SCK
●●
MISO
MOSI
●●
●●
SPI0EN: XBR0.1
NSS
●
● NSS is not assigned to a port pin when the SPI is placed in 3-wire mode
SDA
● ●●●
SCL
● ●●
●●
●●●
SMB0EN: XBR0.0
TX1
● ●●●
RX1
● ●●
●●●●
●●●●●
UART1EN: XBR2.2
CEX0
●
●●●
●●●●●●
CEX1
● ●●
●●●●●●●
CEX2
CEX3
●●
●
●●●●●●●●
●●●●●●●●●
PCA0ME: XBR0.[5:3]
CEX4
●
●●●●●●●●●
CEX5
● ●●●●●●●●●
ECI
●●●●●
●●●●●●●●●●●●
ECI0E: XBR0.6
CP0
●●●●●
●●●●●●●●●●●●●
CP0E: XBR0.7
CP1
●●●●●
●●●●●●●●●●●●●●
CP1E: XBR1.0
T0
●●●●●
●●●●●●●●●●●●●●●
T0E: XBR1.1
/INT0
●●●●●
●●●●●●●●●●●●●●●●
INT0E: XBR1.2
T1
●●●●●
●●●●●●●●●●●●●●●●●
T1E: XBR1.3
/INT1
●●●●●
●●●●●●●●●●●●●●●●●●
INT1E: XBR1.4
T2
●●●●●
●●●●●●●●●●●●●●●●●●●
T2E: XBR1.5
T2EX
●●●●●
●●●●●●●●●●●●●●●●●●●●
T2EXE: XBR1.6
T4
●●●●●
●●●●●●●●●●●●●●●●●●●●●
T4E: XBR2.3
T4EX
●●●●●
●●●●●●●●●●●●●●●●●●●●●●
T4EXE: XBR2.4
/SYSCLK ● ● ● ● ●
●●●●●●●●●●●●●●●●●●●●●●●
SYSCKE: XBR1.7
CNVSTR0 ● ● ● ● ●
● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● CNVSTE0: XBR2.0
CNVSTR2 ● ● ● ● ●
● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● CNVSTE2: XBR2.5
AIN2 Inputs/Non-muxed Addr H Muxed Addr H/Non-muxed Addr L Muxed Data/Non-muxed Data
Figure 18.4. Priority Crossbar Decode Table (EMIFLE = 1; EMIF in Multiplexed
Mode; P1MDIN = 0xFF)
Rev. 1.4
241