
DSC Side Registers
Host Interface Eight (HI8), Rev. 4
Freescale Semiconductor
16-13
16.8.1.8 Host Transmit Interrupt Enable (HTIE)—Bit 1
The Host Transmit Interrupt Enable (HTIE) bit is used to enable a DSC core interrupt when the
Host Transmit Data Empty (HTDE) status bit in the HSR is set. When the HTIE bit is cleared,
HTDE interrupts are disabled. When the HTIE bit is set, a Host Transmit Data Interrupt request
occurs when the HTDE bit is set. The HTIE bit is cleared on hardware reset.
16.8.1.9 Host Receive Interrupt Enable (HRIE)—Bit 0
The Host Receive Interrupt Enable (HRIE) bit is used to enable a DSC core interrupt when the
Host Receive Data Full (HRDF) status bit in the Host Status Register (HSR) is set. When the
HRIE bit is cleared, HRDF interrupts are disabled. When the HRIE bit is set, a Host Receive Data
Interrupt request occurs if the HRDF bit is also set. The HRIE bit is cleared on hardware reset.
16.8.2 HI8 Status Register (HSR)
The 16-bit
read-only
HI8 Status Register (HSR) is used by the DSC to read the status and flags of
the HI8 interface. It cannot be directly accessed by the Host Processor. Reserved bits are read as
0s. The value of the HSR after reset is $0002. All bits are cleared, except for the Host Transmit
Data Empty (HTDE) bit. It is set. The HSR bits are described in the following paragraphs.
Figure 16-6. Host Status Register (HSR)
See Programmer’s Sheet on Appendix page B - 138
16.8.2.1 Reserved—Bits 15–6
These bits are reserved or not implemented. They are read as, and written with 0s.
16.8.2.2 Host DMA Status (HDMA)—Bit 5
The Host DMA Status (HDMA) bit indicates the Host Processor has enabled the Host DMA
mode of the HI8 by setting HM1 or HM0 to 1. When the HDMA status bit is set at 0, it indicates
the Host DMA mode is disabled by the Host mode bits HM0 and HM1, both having been cleared,
in the Interface Control Register ICR and no Host DMA operations are pending. When the
HDMA status bit is set, the Host DMA mode is enabled by the Host mode bits HM0 and HM1.
The transmit or receive channel not in use can be used by the Host for polled or interrupt
operation by the DSC. HDMA is cleared by a DSC reset.
Base + $1
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Read
0
0
0
0
0
0
0
0
0
0
HDMA
HF1
HF0
HCP
HTDE HRDF
Write
0
0
0
0
0
0
0
0
0
0
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0