Interrupts
594
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Sigma-Delta High Speed (SDHS)
22.3 Interrupts
The SDHS support the following interrupt sources:
•
SDHSRIS.OVF (data overflow interrupt):
When the internal buffer overflows, the SDHSRIS.OVF bit
is asserted.
•
SDHSRIS.ACQDONE (acquisition done interrupt):
The SDHSRIS.ACQDONE is asserted when data
conversion has been finished (either complete or incomplete).
If SDHSCTL2.DTOFF = 0, then SDHSRIS.ACQDONE is asserted when the data buffer is empty (that
is, the DTC completes the data transfer).
If SDHSCTL2.DTCOFF = 1, then SDHSRIS.ACQDONE is asserted as the data conversion stops
regardless of the data buffer status. In this case, user can continuously read SDHSDT register until the
data buffer is empty. While reading the SDHSDT register, the data format configuration must not be
changed (SDHSCTL0.DFMSEL, SDHSCTL0.DALGN, and SDHSCTL0.OBR).
•
SDHSRIS.SSTRG (start sampling trigger interrupt):
This bit indicates that the SDHS has started
data conversion.
•
SDHSRIS.DTRDY (data ready interrupt):
This bit is asserted when a new data is available in the data
buffer and remains asserted as long as the data buffer is not empty. The data read by CPU or DTC is
removed from the data buffer. The SDHSRIS.DTRDY bit is deasserted when the data buffer becomes
empty.
•
SDHSRIS.WINHI (window high interrupt):
This bit is asserted when a new output data is higher than
the value in the SDHSWINHITH register.
•
SDHSRIS.WINHL (window low interrupt):
This bit is asserted when a new output data is lower than
the value in the SDHSWINLOTH register.
In addition, the SDHSRIS.ISTOP (incomplete stop status) bit is asserted when the data conversion has
been interrupted without completion. This bit is not an interrupt flag. It can be used as a status bit, not an
interrupt flag.
22.3.1 IIDX, Interrupt Vector Generator
All SDHS interrupt sources are prioritized and combined to source a single interrupt vector. The
SDHSIIDX register is used to determine which enabled SDHS interrupt sources have requested an
interrupt. The SDHSIIDX register generates a value that can be used as address offset for fast interrupt
service routine handling. On each read, only one interrupt is indicated. On a read, the current interrupt
(highest priority) is automatically cleared by the hardware and the corresponding interrupt flag in
SDHSRIS and SDHSMISC are also cleared. After a read from the CPU (not from the debug interface), the
register must be updated with the next highest priority interrupt, if none are pending, then it reads as 0h. If
the interrupt reported by the SDHSIIDX register (highest priority pending interrupt) is cleared in the
SDHSICR by a software write of 1 in the corresponding bit field, the SDHSIIDX register is updated and the
next priority interrupt (if any) is available.
22.4 Debug Mode
When the device is in debug mode, the SDHS cannot be enabled. Writes to the SDHSCTL4.SDHSON and
SDHSCTL5.SSTART bits are prohibited. If the SDHS is already performing data conversion, the data
conversion is stopped automatically and the SDHSRIS.ISTOP bit is asserted (see