PIC16F1847-I/SO Microchip Technology, PIC16F1847-I/SO Datasheet - Page 239

• Manufacturer Part Number: PIC16F1847-I/SO
• Description: 14 KB Flash, 1K Bytes RAM, 32 MHz Int. Osc, 16 I/0, Enhanced Mid Range Core 18 S
• Manufacturer: Microchip Technology

Specifications of PIC16F1847-I/SO

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

25.2.3
The master can initiate the data transfer at any time
because it controls the SCKx line. The master
determines when the slave (Processor 2,
is to broadcast data by the software protocol.
In Master mode, the data is transmitted/received as
soon as the SSPxBUF register is written to. If the SPI
is only going to receive, the SDOx output could be dis-
abled (programmed as an input). The SSPxSR register
will continue to shift in the signal present on the SDIx
pin at the programmed clock rate. As each byte is
received, it will be loaded into the SSPxBUF register as
if a normal received byte (interrupts and Status bits
appropriately set).
FIGURE 25-6:
 2011 Microchip Technology Inc.
Write to
SSPxBUF
SCKx
(CKP = 0
CKE = 0)
SCKx
(CKP = 1
CKE = 0)
SCKx
(CKP = 0
CKE = 1)
SCKx
(CKP = 1
CKE = 1)
SDOx
(CKE = 0)
SDOx
(CKE = 1)
SDIx
(SMP = 0)
Input
Sample
(SMP = 0)
SDIx
(SMP = 1)
Input
Sample
(SMP = 1)
SSPxIF
SSPxSR to
SSPxBUF
SPI MASTER MODE
SPI MODE WAVEFORM (MASTER MODE)
bit 7
bit 7
bit 7
bit 7
bit 6
bit 6
Figure
bit 5
bit 5
25-5)
Preliminary
bit 4
bit 4
bit 3
bit 3
The clock polarity is selected by appropriately
programming the CKP bit of the SSPxCON1 register
and the CKE bit of the SSPxSTAT register. This then,
would give waveforms for SPI communication as
shown in
where the MSB is transmitted first. In Master mode, the
SPI clock rate (bit rate) is user programmable to be one
of the following:
• F
• F
• F
• Timer2 output/2
• Fosc/(4 * (SSPxADD + 1))
Figure 25-6
When the CKE bit is set, the SDOx data is valid before
there is a clock edge on SCKx. The change of the input
sample is shown based on the state of the SMP bit. The
time when the SSPxBUF is loaded with the received
data is shown.
OSC
OSC
OSC
/4 (or T
/16 (or 4 * T
/64 (or 16 * T
bit 2
bit 2
Figure
shows the waveforms for Master mode.
CY
PIC16(L)F1847
)
bit 1
bit 1
25-6,
CY
CY
)
)
Figure 25-8
bit 0
bit 0
bit 0
bit 0
DS41453A-page 239
and
4 Clock
Modes
Figure
25-9,