20-34
MC9328MX1 Reference Manual
MOTOROLA
Multimedia Card/Secure Digital Host Controller Module (MMC/SD)
20.7.2.2 Reset
There are three types of reset available for the MMC/SD module:
•
Hardware reset
—Resets both the card(s) and the MMC/SD module, driven by power on reset
(POR).
•
Software reset
—Resets the MMC/SD module only. This is controlled via the MMC/SD Clock
Control Register (STR_STP_CLK). See Section 20.6.1, “MMC/SD Clock Control Register,” for
more information on software resets.
•
Card reset
—Resets the cards only.
GO_IDLE_STATE
(CMD0) sets the MMC and SD memory
cards into idle state.
IO_RW_DIRECT
(CMD52) resets the SD I/O Card. The cards are initialized
with a default relative card address (RCA = 0x0001) and with a default driver stage register setting
(lowest speed, highest driving current capability).
Code Example 20-4. Software_Reset
software_reset()
{
write_reg(STR_STP_CLK, 0x8);
write_reg(STR_STP_CLK, 0xd);
write_reg(STR_STP_CLK, 0x5);
write_reg(STR_STP_CLK, 0x5);
write_reg(STR_STP_CLK, 0x5);
write_reg(STR_STP_CLK, 0x5);
write_reg(STR_STP_CLK, 0x5);
write_reg(STR_STP_CLK, 0x5);
write_reg(STR_STP_CLK, 0x5);
write_reg(STR_STP_CLK, 0x5);
write_reg(CLK_RATE, 0x3F);
// Set the lowest clock for
// initialization
write_reg(READ_TO, 0x2DB4);
send_cmd_wait_resp(CMD_GO_IDLE_STATE, 0x0, 0x0, 0x80, 0x40);
}
20.7.2.3 Voltage Validation
All cards can communicate with the MMC/SD module using any operating voltage within the specification
range. The supported minimum and maximum Vdd values are defined in the Operation Conditions
Register (OCR) on the card.
Cards that store the card identification number (CID) and card-specific data (CSD) in the payload memory
are able to communicate this information only under data transfer Vdd conditions. When the MMC/SD
module and card have incompatible Vdd ranges, the card is not able to complete the identification cycle
and cannot send CSD data. For this purpose, the special commands
SEND_OP_COND
(CMD1),
SD_APP_OP_COND
(ACMD41 for SD Memory), and
IO_SEND_OP_COND
(CMD5 for SD I/O) are
designed to provide a mechanism to identify and reject cards that do not match the Vdd range desired by
the MMC/SD module. The MMC/SD module sends the required Vdd voltage window as the operand of
these commands. Cards that cannot perform data transfer in the specified range disconnect from the bus
and go to inactive state.
By uses these commands without including the voltage range as the operand, the MMC/SD module can
query each card and determine the common voltage range before sending out-of-range cards into the
inactive state. This query is used when the MMC/SD module is able to select a common voltage range or
when the user requires notification that cards are not usable.
Summary of Contents for DragonBall MC9328MX1
Page 68: ...1 12 MC9328MX1 Reference Manual MOTOROLA Introduction ...
Page 86: ...2 18 MC9328MX1 Reference Manual MOTOROLA Signal Descriptions and Pin Assignments ...
Page 116: ...3 30 MC9328MX1 Reference Manual MOTOROLA Memory Map ...
Page 126: ...4 10 MC9328MX1 Reference Manual MOTOROLA ARM920T Processor ...
Page 160: ...8 8 MC9328MX1 Reference Manual MOTOROLA System Control ...
Page 272: ...13 32 MC9328MX1 Reference Manual MOTOROLA DMA Controller ...
Page 281: ...Programming Model MOTOROLA Watchdog Timer Module 14 9 ...
Page 282: ...14 10 MC9328MX1 Reference Manual MOTOROLA Watchdog Timer Module ...
Page 300: ...15 18 MC9328MX1 Reference Manual MOTOROLA Analog Signal Processor ASP ...
Page 438: ...18 16 MC9328MX1 Reference Manual MOTOROLA Serial Peripheral Interface Modules SPI 1 and SPI 2 ...
Page 478: ...19 40 MC9328MX1 Reference Manual MOTOROLA LCD Controller ...
Page 574: ...21 32 MC9328MX1 Reference Manual MOTOROLA Memory Stick Host Controller MSHC Module ...
Page 598: ...23 16 MC9328MX1 Reference Manual MOTOROLA Real Time Clock RTC ...
Page 670: ...24 72 MC9328MX1 Reference Manual MOTOROLA SDRAM Memory Controller ...
Page 726: ...25 56 MC9328MX1 Reference Manual MOTOROLA SmartCard Interface Module SIM ...
Page 736: ...26 10 MC9328MX1 Reference Manual MOTOROLA General Purpose Timers ...
Page 854: ...29 18 MC9328MX1 Reference Manual MOTOROLA I2C Module ...
Page 900: ...30 46 MC9328MX1 Reference Manual MOTOROLA Synchronous Serial Interface SSI ...
Page 942: ...32 26 MC9328MX1 Reference Manual MOTOROLA GPIO Module and I O Multiplexer IOMUX ...