AT89LP6440 Atmel Corporation, AT89LP6440 Datasheet - Page 102

• Manufacturer Part Number: AT89LP6440
• Manufacturer: Atmel Corporation

Specifications of AT89LP6440

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 38
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 153.8
• Sram (kbytes): 4.25
• Eeprom (bytes): 8192
• Self Program Memory: IAP
• Operating Voltage (vcc): 2.4 to 3.6
• Timers: 3
• Isp: SPI/OCD
• Watchdog: Yes

Table 17-2.
102
SPCR Address = E9H
Not Bit Addressable
Symbol
TSCK
SPE
DORD
MSTR
CPOL
CPHA
Bit
AT89LP3240/6440
TSCK
Function
SCK Clock Mode. When TSCK = 0, the SCK baud rate is based on the system clock, divided by the SPR
TSCK = 1, the SCK baud rate is based on the Timer 1 overflow rate, divided by the SPR
SPI enable. SPI = 1 enables the SPI channel and connects SS, MOSI, MISO and SCK to pins P1.4, P1.5, P1.6, and P1.7.
SPI = 0 disables the SPI channel.
Data order. DORD = 1 selects LSB first data transmission. DORD = 0 selects MSB first data transmission.
Master/slave select. MSTR = 1 selects Master SPI mode. MSTR = 0 selects slave SPI mode.
Clock polarity. When CPOL = 1, SCK is high when idle. When CPOL = 0, SCK of the master device is low when not
transmitting. Please refer to figure on SPI clock phase and polarity control.
Clock phase. The CPHA bit together with the CPOL bit controls the clock and data relationship between master and
slave. Please refer to figure on SPI clock phase and polarity control.
7
SPCR – SPI Control Register
SPE
.
Table 17-1.
Notes:
6
MOSI
MISO
SCK
Pin
1. In these modes MOSI is active only during transfers. MOSI will be pulled high between trans-
2. In Push-Pull mode MOSI is active only during transfers, otherwise it is tristated to prevent line
fers to allow other masters to control the line.
contention. A weak external pull-up may be required to prevent MOSI from floating.
Mode
Quasi-bidirectional
Push-Pull Output
Input-Only
Open-Drain Output
Quasi-bidirectional
Push-Pull Output
Input-Only
Open-Drain Output
Quasi-bidirectional
Push-Pull Output
Input-Only
Open-Drain Output
DORD
5
SPI Pin Configuration and Behavior when SPE = 1
MSTR
4
Master (MSTR = 1)
Output
Output
No output (Tristated)
Output
Output
Output
No output (Tristated)
Output
Input (Internal Pull-up)
Input (Tristate)
Input (Tristate)
Input (External Pull-up)
(1)
(2)
(1)
CPOL
3
CPHA
2
Slave (MSTR = 0)
Input (Internal Pull-up)
Input (Tristate)
Input (Tristate)
Input (External Pull-up)
Input (Internal Pull-up)
Input (Tristate)
Input (Tristate)
Input (External Pull-up)
Output (SS = 0)
Internal Pull-up (SS = 1 or DISSO = 1)
Output (SS = 0)
Tristated (SS = 1 or DISSO = 1)
No output (Tristated)
Output (SS = 0)
External Pull-up (SS = 1 or DISSO = 1)
Reset Value = 0000 0000B
1-0
SPR1
1
ratio.
SPR0
1-0
3706C–MICRO–2/11
0
ratio.When