Rainbow-electronics AT89C5122 Manual do Utilizador Página 141

  • Descarregar
  • Adicionar aos meus manuais
  • Imprimir
  • Página
    / 213
  • Índice
  • MARCADORES
  • Avaliado. / 5. Com base em avaliações de clientes
Vista de página 140
141
AT8xC5122/23
4202E–SCR–06/06
Figure 86. Data Transmission Format (CPHA = 0)
Figure 87. Data Transmission Format (CPHA = 1)
As shown in Figure 86, the first SCK edge is the MSB capture strobe. Therefore the
Slave must begin driving its data before the first SCK edge, and a falling edge on the SS
pin is used to start the transmission. The SS pin must be toggled high and then low
between each byte transmitted (Figure 88).
Figure 88. CPHA/SS
Timing
Figure 87 shows an SPI transmission in which CPHA is1”. In this case, the Master
begins driving its MOSI pin on the first SCK edge. Therefore, the Slave uses the first
SCK edge as a start transmission signal. The SS
pin can remain low between transmis-
MSB bit6 bit5 bit4 bit3 bit2 bit1 LSB
bit6 bit5 bit4 bit3 bit2 bit1MSB
LSB
132 45678
Capture Point
SS (to Slave)
MISO (from Slave)
MOSI (from Master)
SCK (CPOL = 1)
SCK (CPOL = 0)
SPEN (internal)
SCK Cycle Number
MSB bit6 bit5 bit4 bit3 bit2 bit1 LSB
bit6 bit5 bit4 bit3 bit2 bit1
MSB LSB
132 45678
Capture point
SS (to Slave)
MISO (from Slave)
MOSI (from Master)
SCK (CPOL = 1)
SCK (CPOL = 0)
SPEN (internal)
SCK Cycle Number
Byte 1 Byte 2
Byte 3
MISO/MOSI
Master SS
Slave SS
(CPHA = 1)
Slave SS
(CPHA = 0)
Vista de página 140
1 2 ... 136 137 138 139 140 141 142 143 144 145 146 ... 212 213

Comentários a estes Manuais

Sem comentários