C8051F300/1/2/3/4/5
20
Rev. 2.9
Perhaps the most unique Port I/O enhancement is the Digital Crossbar. This is essentially a digital switch-
ing network that allows mapping of internal digital system resources to Port I/O pins (See Figure 1.7). On-
chip counter/timers, serial buses, HW interrupts, comparator output, and other digital signals in the control-
ler can be configured to appear on the Port I/O pins specified in the Crossbar Control registers. This allows
the user to select the exact mix of general purpose Port I/O and digital resources needed for the particular
application.
Figure 1.7. Digital Crossbar Diagram
1.5.
Serial Ports
The C8051F300/1/2/3/4/5 Family includes an SMBus/I
2
C interface and a full-duplex UART with enhanced
baud rate configuration. Each of the serial buses is fully implemented in hardware and makes extensive
use of the CIP-51's interrupts, thus requiring very little CPU intervention.
XBR0, XBR1,
XBR2 Registers
Digital
Crossbar
Priority
Decoder
SYSCLK
2
2
(In
te
rnal D
igital Sign
als)
Highest
Priority
Lowest
Priority
P0
I/O
Cells
P0.0
P0.7
8
P0MDOUT,
P0MDIN Registers
SMBus
UART
T0, T1
2
4
PCA
P0
Port Latch
(P0.0-P0.7)
8
CP0
Outputs
2
Summary of Contents for C8051F300
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