MC72000 Freescale Semiconductor, MC72000 Datasheet - Page 66

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

Hardware Functional Description
7.3.5.4 SS_B — SPI Slave Select
The SS_B pin has various functions depending on the current state of the CSPI CONTROLREG. For a CSPI
configured as a slave, the SS_B pin is used to select a slave. When a CSPI is configured as a slave, the SS_B
pin is always configured as an input. It cannot be used as a general purpose I/O.
When a CSPI is configured as a master, for PHA = 1, the SS_B is used to define the start of a new word
transmission. However, it can remain low between word transmissions for the PHA = 0 format.
When enabled in the GPIO function select register, the CSPI controls data direction of the SS_B pin
regardless of the state of the GPIO data direction register of the shared I/O port.
7.3.5.5 DATAREADY_B — SPI Data Ready
The DATAREADY_B pin is used in master mode to allow a slave device to signal the master that the slave
is ready to deliver some new data to the master.
When enabled in the GPIO function select register, the CSPI controls data direction of the
DATAREADY_B pin regardless of the state of the GPIO data direction register of the shared I/O port.
7.3.6 Memory Map and Registers
Table 29 shows the CSPI memory map. There are 8 user programmable registers which are 16 bits. All
registers are aligned to the 32-bit word address width and always return zeros in the upper 16 bits whenever
read. The AIPI can be set to enable the CRM for either 32- or 16- bit transfers. All registers are byte and
halfword accessible. The base address of the CSPI0 and CSPI1 modules on the MC72000 is 32’h8000_8000
and 32’h8000_9000.
The following sections provide detailed descriptions of each of the CSPI registers. All readable registers
will return 0x0 after reset unless otherwise specifically stated. All reserved bits are read as zero and should
be written with zero for future compatibility.
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Base + 0x0C
Base + 0x00
Base + 0x04
Base + 0x08
Base + 0x10
Base + 0x14
Base + 0x18
Base + 0x1c
Address
Freescale Semiconductor, Inc.
RX Data Register (RXDATAREG)
TX Data Register (TXDATAREG)
Control Register (CONTROLREG)
Interrupt Control/Status Register (INTREG)
CSPI Test Register (TESTREG)
CSPI Sample Period Control Register (PERIODREG)
Reserved
CSPI Soft Reset Register (RESETREG)
For More Information On This Product,
MC72000 Advance Information Data Sheet
Table 29. CSPI Memory Map
Go to: www.freescale.com
Preliminary
Use
Access
R/W
R/W
R/W
R/W
R/W
R/W
N/A
R
MOTOROLA