C8051F045R Silicon Labs, C8051F045R Datasheet - Page 188

• Manufacturer Part Number: C8051F045R
• Description: 8-bit Microcontrollers - MCU 25 MIPS 64KB 10ADC
• Manufacturer: Silicon Labs

Specifications of C8051F045R

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 25 MHz
• Program Memory Size: 64 KB
• Data Ram Size: 4.25 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.7 V to 3.6 V
• Package / Case: TQFP-64
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 13
• Data Rom Size: 64 KB
• Interface Type: CAN, SMBus, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 32
• Number Of Timers: 16 bit
• Processor Series: C8051
• Program Memory Type: Flash
• Factory Pack Quantity: 500
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 2.7 V

C8051F040/1/2/3/4/5/6/7
16.2. Configuring the External Memory Interface
Configuring the External Memory Interface consists of five steps:
Each of these five steps is explained in detail in the following sections. The Port selection, Multiplexed
mode selection, and Mode bits are located in the EMI0CF register shown in SFR Definition 16.2.
16.3. Port Selection and Configuration
The External Memory Interface can appear on Ports 3, 2, 1, and 0 (C8051F04x devices) or on Ports 7, 6,
5, and 4 (C8051F040/2/4/6 devices only), depending on the state of the PRTSEL bit (EMI0CF.5). If the
lower Ports are selected, the EMIFLE bit (XBR2.1) must be set to a ‘1’ so that the Crossbar will skip over
P0.7 (/WR), P0.6 (/RD), and, if multiplexed mode is selected, P0.5 (ALE). For more information about the
configuring the Crossbar, see
page
The External Memory Interface claims the associated Port pins for memory operations ONLY during the
execution of an off-chip MOVX instruction. Once the MOVX instruction has completed, control of the Port
pins reverts to the Port latches or to the Crossbar (on Ports 3, 2, 1, and 0). See
Output” on page 203
Port latches should be explicitly configured as push-pull to ‘park’ the External Memory Interface
pins in a dormant state, most commonly by setting them to a logic 1.
During the execution of the MOVX instruction, the External Memory Interface will explicitly disable the driv-
ers on all Port pins that are acting as Inputs (Data[7:0] during a READ operation, for example). The Output
mode of the Port pins (whether the pin is configured as Open-Drain or Push-Pull) is unaffected by the
External Memory Interface operation, and remains controlled by the PnMDOUT registers. In most cases,
the output modes of all EMIF pins should be configured for push-pull mode. See
“17.1.2. Configuring the Output Modes of the Port Pins” on page
188
204.
1. Select EMIF on Low Ports (P3, P2, P1, and P0) or High Ports (P7, P6, P5, and P4).
2. Configure the Output Modes of the port pins as either push-pull or open-drain.
3. Select Multiplexed mode or Non-multiplexed mode.
4. Select the memory mode (on-chip only, split mode without bank select, split mode with bank
5. Set up timing to interface with off-chip memory or peripherals.
select, or off-chip only).
for more information about the Crossbar and Port operation and configuration. The
Section “17.1. Ports 0 through 3 and the Priority Crossbar Decoder” on
Rev. 1.5
206.
Section “17. Port Input/
Section