Maxim Integrated MAX32665 - Table 8-83: SDHC Capabilities Register 0

MAX32665-MAX32668 User Guide
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Host Control 2 Register
SDHC_HOST_CN_2
[0x003E]
Bits
Name
Access
Reset
Description
7
sampling_clk
R/W
0
Sampling Clock Select
This field is automatically set by hardware when Execute Tuning
(SDHC_HOST_CN_2. execute) is cleared.
0: The fixed clock is used to sample data
1: The tuned clock is used to sample data
Note: The Card Driver cannot write 1 to this bit. Writing this bit to 0 can only be
done if the Host Controller is not receiving a response or reading a data block.
6
execute
R/WAC
0
Execute Tuning
Setting this bit to 1 starts the tuning procedure and the bit is automatically
cleared when the Host Controller completes the tuning procedure. Writing a 0
to this bit when it is set to 1 aborts the tuning procedure.
1: Execute tuning
0: Tuning complete or not tuned
5:4
driver_strength
R/W
0
Driver Strength Select
If using 3.3V signaling, this field is ignored. For 1.8V signaling, the output driver
strength is set using this field.
If SDHC_HOST_CN_2.preset_val_en = 0, this field is controlled by the Host
Driver. If SDHC_HOST_CN_2.preset_val_en = 1, this field is automatically set by
the hardware using the Preset Value registers.
00b: Driver Type B is selected
01b: Driver Type A is selected
10b: Driver Type C is selected
11b: Driver Type D is selected
3
1_8v_signal
R/W
0
1.8V Signaling Enable
If the card inserted supports UHS-I, this bit can be set to 1. No matter the value
set, 3.3V is used for the card’s supply.
1: 1.8V signaling
0: 3.3V signaling
2:0
uhs
R/W
0
UHS Mode Select
Used to select the UHS-I mode. This field is only used if 1.8V signaling is set to 1
(SDHC_HOST_CN_2.1_8v_signal = 1).
000b: SDR12
001b: SDR25
010b: SDR50
011b: SDR104 (Not supported)
100b: DDR50
101b – 111b: Reserved for Future Use
Table 8-83: SDHC Capabilities Register 0
Capabilities Register 0
SDHC_CFG_0
[0x0040]
Bits
Name
Access
Reset
Description
31:30
slot_type
RO
0b00
Slot Type
0b00: Support for a single slot with support for a removable card
29
async_int
RO
1
Asynchronous Interrupt Support
1: Asynchronous Interrupt Supported
28
64_bit_sys_bus
RO
0
64-bit System Bus Support
0: 64-bit system bus not supported