Control Registers
1208
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Multi-Buffered Serial Peripheral Interface Module (MibSPI) with Parallel Pin
Option (MibSPIP)
24.9.43 I/O-Loopback Test Control Register (IOLPBKTSTCR)
This register controls test mode for I/O pins. It also controls whether loop-back should be digital or analog.
In addition, it contains control bits to induce error conditions into the module. These are to be used only for
module testing.
All of the control/status bits in this register are valid only when the IOLPBKTSTENA field is set to Ah.
Figure 24-73. I/O-Loopback Test Control Register (IOLPBKTSTCR) [offset = 134h]
31
25
24
Reserved
SCS_FAIL_
FLG
R-0
R/W1C-0
23
21
20
19
18
17
16
Reserved
CTRL_
BITERR
CTRL_
DESYNC
CTRL_
PARERR
CTRL_
TIMEOUT
CTRL_
DLENERR
R-0
R/WP-0
R/WP-0
R/WP-0
R/WP-0
R/WP-0
15
12
11
8
Reserved
IOLPBKTSTENA
R-0
R/WP-0
7
6
5
3
2
1
0
Reserved
ERR_SCS_PIN
CTRL_SCS_
PIN_ERR
LPBKTYPE
RXPENA
R-0
R/WP-0
R/WP-0
R/WP-0
R/WP-0
LEGEND: R/W = Read/Write; R = Read only; W1C = Write 1 to clear; WP = Write in privilege mode only; -
n
= value after reset
Table 24-51. I/O-Loopback Test Control Register (IOLPBKTSTCR) Field Descriptions
Bit
Field
Value
Description
31-25
Reserved
0
Reads return 0. Writes have no effect.
24
SCS FAIL FLG
Bit indicating a failure on SPICS pin compare during analog loopback.
0
Read: No miscompares occurred on any of the eight chip select pins (vs. the internal
chip select number CSNR during transfers).
Write: Writing a 0 to this bit has no effect.
1
Read: A comparison between the internal CSNR field and the analog looped-back
value of one or more of the SPICS pins failed. A stuck-at fault is detected on one of the
SPICS pins. Comparison is done only on the pins that are configured as functional and
during transfer operation.
Write: This flag bit is cleared.
23-21
Reserved
0
Reads return 0. Writes have no effect.
20
CTRL BITERR
Controls inducing of BITERR during I/O loopback test mode.
0
Do not interfere with looped-back data.
1
Induces bit errors by inverting the value of the incoming data during loopback.
19
CTRL DESYNC
Controls inducing of the desync error during I/O loopback test mode.
0
Do not cause a desync error.
1
Induce a desync error by forcing the incoming SPIENA pin (if functional) to remain 0
even after the transfer is complete. This forcing will be retained until the kernel reaches
the idle state.
18
CTRL PARERR
Controls inducing of the parity errors during I/O loopback test mode.
0
Do not cause a parity error.
1
Induce a parity error by inverting the polarity of the parity bit.
17
CTRL TIMEOUT
Controls inducing of the timeout error during I/O loopback test mode.
0
Do not cause a timeout error.
1
Induce a timeout error by forcing the incoming SPIENA pin (if functional) to remain 1
when transmission is initiated. The forcing will be retained until the kernel reaches the
idle state.