Control Registers
1210
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Multi-Buffered Serial Peripheral Interface Module (MibSPI) with Parallel Pin
Option (MibSPIP)
24.9.44 SPI Extended Prescale Register 1 (EXTENDED_PRESCALE1 for SPIFMT0 and
SPIFMT1)
This register provides an extended Prescale values for SPICLK generation to be able to interface with
much slower SPI Slaves. This is an extension of SPIFMT0 and SPIFMT1 registers. For example,
EPRESCALE_FMT1[7:0] of EXTENDED_PRESCALE1 and PRESCALE1 of SPIFMT1 register will always
reflect the same contents. Similarly, EPRESCALE_FMT0[7:0] and PRESCALE0 of SPIFMT0 reflect the
same contents.
Figure 24-74. SPI Extended Prescale Register 1 (EXTENDED_PRESCALE1 for SPIFMT0 and
SPIFMT1) [offset = 138h]
31
27
26
16
Reserved
EPRESCALE_FMT1
R-0
R/WP-0
15
11
10
0
Reserved
EPRESCALE_FMT0
R-0
R/WP-0
LEGEND: R/W = Read/Write; R = Read only; WP = Write in privilege mode only; -
n
= value after reset
Table 24-52. SPI Extended Prescale Register 1 (EXTENDED_PRESCALE1) Field Descriptions
Bit
Field
Value
Description
31-27
Reserved
0
Reads return 0. Writes have no effect.
26-16
EPRESCALE_FMT1
0-7FFh
EPRESCALE_FMT1. Extended Prescale value for SPIFMT1. EPRESCALE_FMT1
determines the bit transfer rate of data format 1 if the SPI/MibSPI is the network master.
EPRESCALE_FMT1 is use to derive SPICLK from VCLK. If the SPI is configured as
slave, EPRESCALE_FMT1
does not need
to be configured. These
EPRESCALE_FMT1[7:0] bits and PRESCALE1 bits of SPIFMT1 register will point to the
same physically implemented register. The clock rate for data format 1 can be calculated
as:
BR
Format1
= VCLK / (EPRESCAL 1)
Write: This register field should be written if a SPICLK prescaler of more VCLK/256 is
required. This field provides a prescaler of up to VCLK/2048 for SPICLK. Writing to this
register field will also get reflected in the PRESCALE1 bits of SPIFMT1 register.
Read: Reading this field will reflect the PRESCALE value based on the last written
register field, that is, EXTENDED_PRESCALE1[26:16] or SPIFMT1[15:8] register.
Note: If Extended Prescaler is required, it should be ensured that
EXTENDED_PRESCALE1 register is programmed after SPIFMT1 register is
programmed. This is to ensure that the final SPICLK prescale value is controlled by
EXTENDED_PRESCALE1 register when a prescale of more 256 is intended on
SPICLK. Writing to PRESCALE1 field of SPIFMT1 will automatically clear
EPRESCALE_FMT1[10:8] bits to 000 so that the integrity of PRESCALE value is
maintained.
15-11
Reserved
0
Reads return 0. Writes have no effect.