C8051F987-GMR Silicon Labs, C8051F987-GMR Datasheet - Page 26

• Manufacturer Part Number: C8051F987-GMR
• Description: 8-bit Microcontrollers - MCU 8kB 512B RAM
• Manufacturer: Silicon Labs

Specifications of C8051F987-GMR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051F99x-C8051F98x
1.2.
Digital and analog resources are available through 16 or 17 I/O pins. Port pins are organized as three byte-
wide ports. Port pins P0.0–P1.7 can be defined as digital or analog I/O. Digital I/O pins can be assigned to
one of the internal digital resources or used as general purpose I/O (GPIO). Analog I/O pins are used by
the internal analog resources. P2.7 can be used as GPIO and is shared with the C2 Interface Data signal
(C2D). See Section “27. C2 Interface” on page 317 for more details.
The designer has complete control over which digital and analog functions are assigned to individual Port
pins, limited only by the number of physical I/O pins. This resource assignment flexibility is achieved
through the use of a Priority Crossbar Decoder. See Section “21.3. Priority Crossbar Decoder” on
page 217 for more information on the Crossbar.
All Port I/Os can tolerate voltages up to the supply rail when used as digital inputs or open-drain outputs.
For Port I/Os configured as push-pull outputs, current is sourced from the VDD supply. Port I/Os used for
analog functions can operate up to the VDD supply voltage. See Section “21.1. Port I/O Modes of
Operation” on page 214 for more information on Port I/O operating modes and the electrical specifications
chapter for detailed electrical specifications.
26
Highest
Priority
Lowest
Priority
Port Input/Output
SYSCLK
SMBus
Output
T0, T1
UART
P0
P1
P2
SPI0
CP0
PCA
(P0.0-P0.7)
(P1.0-P1.7)
(P2.7)
Figure 1.14. Port I/O Functional Block Diagram
2
4
2
4
4
2
8
8
1
Rev. 1.1
XBR2, PnSKIP
XBR0, XBR1,
Crossbar
Decoder
Registers
Priority
Digital
(ADC0, CP0, and CP1 inputs,
To Analog Peripherals
VREF, IREF0, AGND)
8
8
1
P0MASK, P0MAT
P1MASK, P1MAT
Port Match
Cells
Cells
Cell
I/O
I/O
I/O
P0
P1
P2
PnMDIN Registers
External Interrupts
EX0 and EX1
PnMDOUT,
*P1.5 is not available on
20-pin devices.
P0.0
P0.7
P1.0
P1.7*
P2.7