C8051T630DK Silicon Laboratories Inc, C8051T630DK Datasheet - Page 114

• Manufacturer Part Number: C8051T630DK
• Description: KIT DEV FOR C8051T630 FAMILY
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051T630DK

• Contents: Board, daughter boards, power adapter, cables, documentation and software
• Processor To Be Evaluated: C8051T63x
• Interface Type: USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051T630, T631, T632, T633, T634 and T635 MCUs
• For Use With: 336-1465 - BOARD SOCKET DAUGHTER 20-QFN
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1464

C8051T630/1/2/3/4/5
20.3. Priority Crossbar Decoder
The Priority Crossbar Decoder (Figure 20.3) assigns a priority to each I/O function, starting at the top with
UART0. When a digital resource is selected, the least-significant unassigned Port pin is assigned to that
resource (excluding UART0, which is always at pins 4 and 5). If a Port pin is assigned, the Crossbar skips
that pin when assigning the next selected resource. Additionally, the Crossbar will skip Port pins whose
associated bits in the PnSKIP registers are set. The PnSKIP registers allow software to skip Port pins that
are to be used for analog input, dedicated functions, or GPIO.
Important Note on Crossbar Configuration: If a Port pin is claimed by a peripheral without use of the
Crossbar, its corresponding PnSKIP bit should be set. This applies to P0.0 if VREF is used, P0.3 if the
external oscillator circuit is enabled, P0.6 if the ADC or IDAC is configured to use the external conversion
start signal (CNVSTR), and any selected ADC or Comparator inputs. The Crossbar skips selected pins as
if they were already assigned, and moves to the next unassigned pin. Figure 20.3 shows the Crossbar
Decoder priority with no Port pins skipped (P0SKIP, P1SKIP = 0x00); Figure 20.4 shows the Crossbar
Decoder priority with the V
114
SF Signals
PIN I/O
TX0
RX0
SCK
MISO
MOSI
NSS*
SDA
SCL
CP0
CP0A
SYSCLK
CEX0
CEX1
CEX2
ECI
T0
T1
SF Signals
Figure 20.3. Crossbar Priority Decoder with No Pins Skipped
VREF IDA
Port pin potentially available to peripheral
Special Function Signals are not assigned by the crossbar.
When these signals are enabled, the CrossBar must be
manually configured to skip their corresponding port pins.
0
0
1
0
PP
(P0.2) and EXTCLK(P0.3) pins skipped (P0SKIP = 0x0C).
2
0
EXTCLK
P0SKIP[0:7]
3
0
P0
4
0
*NSS is only pinned out in 4-wire SPI Mode
5
0
CNVSTR
Rev. 1.0
6
0
7
0
0
0
1
0
2
0
P1SKIP[0:7]
3
0
P1
4
0
5
0
6
0
7
0
P2
0