Serial Peripheral Interface Module (SPI)

SPE — SPI Enable Bit

This read/write bit enables the SPI module. Clearing SPE causes a partial reset of the SPI. See 15.8 Resetting the SPI. Reset clears the SPE bit.

1 = SPI module enabled

0 = SPI module disabled

SPTIE— SPI Transmit Interrupt Enable Bit

This read/write bit enables CPU interrupt requests generated by the SPTE bit. SPTE is set when a byte transfers from the transmit data register to the shift register. Reset clears the SPTIE bit.

1 = SPTE CPU interrupt requests enabled

0 = SPTE CPU interrupt requests disabled

15.12.2 SPI Status and Control Register

The SPI status and control register (SPSCR) contains flags to signal these conditions:

•Receive data register full

•Failure to clear SPRF bit before next byte is received (overflow error)

•Inconsistent logic level on SS pin (mode fault error)

•Transmit data register empty

The SPI status and control register also contains bits that perform these functions:

•Enable error interrupts

•Enable mode fault error detection

•Select master SPI baud rate

Address:

$0045

 

 

 

 

 

 

 

 

Bit 7

6

5

4

3

2

1

Bit 0

 

 

 

 

 

 

 

 

 

Read:

SPRF

ERRIE

OVRF

MODF

SPTE

MODFEN

SPR1

SPR0

 

 

 

 

 

Write:

R

R

R

R

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset:

0

0

0

0

1

0

0

0

 

 

 

 

 

 

 

 

 

 

R

= Reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 15-15. SPI Status and Control Register (SPSCR)

SPRF — SPI Receiver Full Bit

This clearable, read-only flag is set each time a byte transfers from the shift register to the receive data register. SPRF generates a CPU interrupt request if the SPRIE bit in the SPI control register is set also.

During an SPRF CPU interrupt (DMAS = 0), the CPU clears SPRF by reading the SPI status and control register with SPRF set and then reading the SPI data register.

Reset clears the SPRF bit.

1 = Receive data register full

0 = Receive data register not full

ERRIE — Error Interrupt Enable Bit

This read/write bit enables the MODF and OVRF bits to generate CPU interrupt requests. Reset clears the ERRIE bit.

1 = MODF and OVRF can generate CPU interrupt requests.

0 = MODF and OVRF cannot generate CPU interrupt requests.

MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1

212

Freescale Semiconductor

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Freescale Semiconductor MC68HC908MR32, MC68HC908MR16 manual SPI Status and Control Register, SPE SPI Enable Bit
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MC68HC908MR16, MC68HC908MR32 specifications

Freescale Semiconductor's MC68HC908MR32 and MC68HC908MR16 microcontrollers are part of the popular HC08 family, designed primarily for embedded applications. These microcontrollers are particularly favored in automotive, industrial, and consumer product sectors due to their reliability and versatility.

One of the standout features of the MC68HC908MR series is its CMOS technology, which enhances performance while minimizing power consumption. This makes these microcontrollers suitable for battery-operated devices. They operate at a maximum clock frequency of 2 MHz and offer a 16-bit architecture, providing a solid balance between processing power and efficiency.

The MC68HC908MR32 variant is equipped with 32KB of flash memory, which allows for the storage of complex programs and extensive data handling. In contrast, the MC68HC908MR16 features 16KB of flash memory, making it ideal for simpler applications. Both microcontrollers also come with 1KB of RAM, enabling efficient data processing and real-time operations.

Another significant characteristic of these microcontrollers is their integrated peripherals. They come with multiple input/output (I/O) pins, which allow for connectivity with various sensors and actuators. The built-in timer systems offer precise timing control for automotive and industrial applications, while the Analog-to-Digital Converter (ADC) provides essential conversion capabilities for various analog signals.

For communication purposes, the MC68HC908MR series includes a serial communication interface, enabling easy integration with other devices and systems. This versatility facilitates the development of complex systems that require interaction with external components.

Security is another crucial aspect of these microcontrollers. They have built-in fail-safe mechanisms to ensure reliable operation under various conditions, making them suitable for critical systems. Additionally, their robust architecture helps to safeguard against potential disruptions or attacks.

In summary, Freescale Semiconductor's MC68HC908MR32 and MC68HC908MR16 microcontrollers are key players in the embedded systems landscape. Their blend of power efficiency, integrated features, and scalability ensures they remain relevant for a wide array of applications, making them a favored choice among engineers and developers looking for dependable solutions in a competitive market.
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