Architecture
978
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Host Port Interface (HPI)
21.2.12 Emulation Considerations
The FREE and SOFT bits in the power and emulation management register (PWREMU_MGMT)
determine the response of the HPI to an emulation suspend condition. If FREE = 1, the HPI is not
affected, and the SOFT bit has no effect. If FREE = 0 and SOFT = 0, the HPI is not affected. If FREE = 0
and SOFT = 1:
•
The HPI DMA logic halts after the current host and HPI DMA operations are completed.
•
The external host interface functions as normal throughout the emulation suspend condition. The host
may access the control register (HPIC). The host may also access the HPIA registers and may perform
data reads until the read FIFO is empty or data writes until the write FIFO is full. As in normal
operation, UHPI_HRDY is driven low during a host cycle that cannot be completed due to the write
FIFO being full or the read FIFO being empty. If this occurs, UHPI_HRDY continues to be driven low,
holding off the host, until the emulation suspend condition is over, and the FIFOs are serviced by the
HPI DMA logic, allowing the host cycle to complete.
•
When the emulation suspend condition is over, the appropriate requests by the HPI DMA logic are
made to process any posted host writes in the write FIFO or to fill the read FIFO as necessary. HPI
operation then continues as normal.
21.3 Registers
lists the memory-mapped registers for the HPI. See your device-specific data manual for the
memory addresses of these registers.
Table 21-6. HPI Registers
Offset
Acronym
Register Description
Section
0
REVID
Revision Identification Register
4h
PWREMU_MGMT
Power and Emulation Management Register
Ch
GPIO_EN
GPIO Enable Register
10h
GPIO_DIR1
GPIO Direction 1 Register
14h
GPIO_DAT1
GPIO Data 1 Register
18h
GPIO_DIR2
GPIO Direction 2 Register
1Ch
GPIO_DAT2
GPIO Data 2 Register
30h
HPIC
Host Port Interface Control Register
34h
HPIAW
Host Port Interface Write Address Register
38h
HPIAR
Host Port Interface Read Address Register