MC72000 Freescale Semiconductor, MC72000 Datasheet - Page 86

• Manufacturer Part Number: MC72000
• Description: Integrated Bluetooth Radio
• Manufacturer: Freescale Semiconductor

RESET:
W
Hardware Functional Description
7.4.5.2.5
The RXFIFO is a 7 x 16-bit FIFO register used to buffer samples received in the SSI receive data register
(SXR). The receive FIFO is enabled by setting the RFEN bit of the SCR2 control register. Received data is
then held in the FIFO if the data in the SRX has not yet been read.
If the receive interrupt is enabled, it is asserted whenever the SRX is full and the data level in the SSI receive
FIFO reaches the selected threshold. If the receive FIFO feature is not enabled, this register is bypassed and
the receive shift register (RXSR) data is automatically transferred into the SRX.
7.4.5.2.6
RXSR is a 16-bit shift register that receives incoming data from the serial receive data SRXD pin. When a
continuous clock is used, data is shifted in by the selected (internal/external) bit clock when the associated
(internal/external) frame sync is asserted. When a gated clock is used, data is shifted in by the selected
(internal/external) gated clock. Data is assumed to be received MSB first if the SHFD bit of the SCR2 is
cleared. If this bit is set, the data is received LSB first. Data is transferred to the SSI receive data register
(SRX) or receive FIFO (if the receive FIFO is enabled and SRX is full) after 8, 10, 12, or 16 bits have been
shifted in depending on the WL[1:0] control bits. For receiving 8, 10, or 12 bits data, LSB bits are set to zero.
See Figure 55 and Figure 56 for more information.
86
R
RXSR
15
0
14
= Unimplemented or Reserved
0
SSI Receive FIFO Register (RXFIFO)
SSI Receive Shift Register (RXSR)
15
15
13
0
12
high byte
Freescale Semiconductor, Inc.
0
For More Information On This Product,
MC72000 Advance Information Data Sheet
Figure 55. Receive Data Path (RSHFD=0)
11
0
Figure 54. SRX Register Diagram
Go to: www.freescale.com
10
0
8 bits
8
Base + 0x02
Preliminary
9
0
7
10 bits
8
0
12 bits
7
0
6
0
5
0
0
0
4
0
low byte
SRX
16 bits
3
0
MOTOROLA
2
0
SRXD
1
0
0
0