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TMS320DM6437
Digital Media Processor
SPRS345B–NOVEMBER 2006–REVISED MARCH 2007
–
–
The C64x+ begins execution from the internal bootloader ROM at address 0x00100000.
Depending on the FASTBOOT, AEM[2:0], and PLLMS[2:0] settings, the bootloader code may
program the PLLC1 to PLL Mode to speed up the boot process. See
Table 3-5
,
Table 3-6
, and
Table 3-7
.
The bootloader code reads the code from EMIFA (NAND) EM_CS2 (address 0x42000000) using
AIS format.
EMIFA is configured in NAND mode. The user is responsible for ensuring the desirable
Asynchronous EMIF pins are available through configuration pins AEM[2:0] and AEAW[2:0].
AEM[2:0]
can
be configured to 001b [8-bit EMIFA (Async) Pinout Mode 1], 011b [8-bit EMIFA
(Async) Pinout Mode 3], 100b [8-bit EMIFA (NAND) Pinout Mode 4], or 101b [8-bit EMIFA (NAND)
Pinout Mode 5].
Serial Boot Modes (I2C, UART[UART0], SPI[McBSP0])
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3.4.1.4
This subsection discusses how the bootloader configures the clock dividers for the serial boot modes—I2C
boot, UART boot, and SPI boot.
3.4.1.4.1
I2C Boot
If FASTBOOT = 0, then I2C Boot (BOOTMODE = 0101) is performed in Standard-Mode (up-to 100 kbps).
If FASTBOOT = 1, then I2C Boot is performed in Fast-Mode (up-to 400 kbps). The actual I2C data
transfer rate is dependent on the MXI/CLKIN frequency.
This is how the bootloader programs the I2C:
I2C Boot in Fast-Mode (BOOTMODE[3:0] = 0101b, FASTBOOT = 1)
–
I2C register settings: ICPSC.IPSC = 2
10
, ICCLKL.ICCL = 8
10
, ICCKH.ICCH = 8
10
–
Resulting in the following I2C prescaled module clock frequency (internal I2C clock):
(CLKIN frequency in MHz) / 3
–
Resulting in the following I2C serial clock (SCL):
SCL frequency (in kHz) = (CLKIN frequency in MHz) / 78 * 1000
SCL low pulse duration (in
μ
s) = 39 / (CLKIN frequency in MHz)
SCL high pulse duration (in
μ
s) = 39 / (CLKIN frequency in MHz)
I2C Boot in Standard-Mode (BOOTMODE[3:0] = 0101b, FASTBOOT = 0)
–
I2C register settings: ICPSC.IPSC = 2
10
, ICCLKL.ICCL = 45
10
, ICCKH.ICCH = 45
10
–
Resulting in the following I2C prescaled module clock frequency (internal I2C clock):
(CLKIN frequency in MHz) / 3
–
Resulting in the following I2C serial clock (SCL):
SCL frequency (in kHz) = (CLKIN frequency in MHz) / 300 * 1000
SCL low pulse duration (in
μ
s) = 150 / (CLKIN frequency in MHz)
SCL high pulse duration (in
μ
s) = 150 / (CLKIN frequency in MHz)
Note
: the I2C peripheral requires that the prescaled module clock frequency
must
be between 7 MHz and
12 MHz. Therefore, the I2C boot is
only
available for MXI/CLKIN frequency between 21 MHz and 30 MHz.
For more details on the I2C periperhal configurations and clock requirements, see the
TMS320DM643x
DMP Inter-Integrated Circuit (I2C) Peripheral
User’s Guide (literature number
SPRU991
).
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Device Configurations
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