PCIF0 datasheet(156/294 Pages) ATMEL

Nome de Peças	PCIF0

Descrição Electrónicos	High Performance, Low Power Atmel AVR 8-bit Microcontroller Advanced RISC Architecture

PDF	294 Pages

Scroll/Zoom	100%

Fabricante Electrônico	ATMEL [ATMEL Corporation]

Página de início	http://www.atmel.com

Logo

156 / 294 page

156

9219A–RFID–01/11

Atmel ATA5505 [Preliminary]

14.3.3

SPI Slave Operation Example

The following code demonstrates how to use the USI module as a SPI Slave:

init:

ldi

r16,(1<<USIWM0)|(1<<USICS1)

sts

USICR,r16

...

SlaveSPITransfer:

sts

USIDR,r16

ldi

r16,(1<<USIOIF)

sts

USISR,r16

SlaveSPITransfer_loop:

lds

r16, USISR

sbrs

r16, USIOIF

rjmp

SlaveSPITransfer_loop

lds

r16,USIDR

ret

The code is size optimized using only eight instructions (+ ret). The code example assumes

that the DO is configured as output and USCK pin is configured as input in the DDR Register.

The value stored in register r16 prior to the function is called is transferred to the master

device, and when the transfer is completed the data received from the Master is stored back

into the r16 Register.

Note that the first two instructions is for initialization only and needs only to be executed

once.These instructions sets Three-wire mode and positive edge USI Data Register clock.

The loop is repeated until the USI Counter Overflow Flag is set.

14.3.4

Two-wire Mode

The USI Two-wire mode is compliant to the Inter IC (TWI) bus protocol, but without slew rate

limiting on outputs and input noise filtering. Pin names used by this mode are SCL and SDA.

PCIF0 Folha de dados(PDF) 156 Page - ATMEL Corporation

PCIF0 Folha de dados(HTML) 156 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Folha de dados Download

Ligação URL