Texas Instruments TMS320DM643X DMP Emac Control Module Interrupt Timer Count Register Ewinttcnt

Models: TMS320DM643X DMP

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EMAC Control Module Registers

3.2EMAC Control Module Interrupt Timer Count Register (EWINTTCNT)

The EMAC control module interrupt timer count register (EWINTTCNT) is used to control the generation of back-to-back interrupts from the EMAC and MDIO modules. The value of this timer count is loaded into an internal counter every time interrupts are enabled using the INTEN bit in the EMAC control module interrupt control register (EWCTL). A second interrupt cannot be generated until this count reaches 0. The counter is decremented at a frequency of PLL1clock/6; the default reset count is 0 (inactive) and the maximum value is 1 FFFFh (131 071).

The EWINTTCNT is shown in Figure 12 and described in Table 9.

Figure 12. EMAC Control Module Interrupt Timer Count Register (EWINTTCNT)

31

17

16

Reserved

 

EWINTTCNT

R-0

 

R/W-0

15

 

0

EWINTTCNT

 

 

R/W-0

LEGEND: R = Read only; R/W = Read/Write; -n= value after reset

Table 9. EMAC Control Module Interrupt Timer Count Register (EWINTTCNT) Field Descriptions

Bit

Field

Value

Description

31-18

Reserved

0

Reserved

17-0

EWINTTCNT

0-1 FFFFh

Interrupt timer count. EWINTTCNT is a 17-bit interrupt timer count that is used to control the

 

 

 

generation of back-to-back interrupts from the EMAC and MDIO modules. The value of

 

 

 

EWINTTCNT is loaded in an internal time counter every time interrupts are enabled by

 

 

 

writing a 1 to the INTEN bit in EWCTL (note the INTEN bit must transition from 0 to 1 to

 

 

 

initialize the internal time counter). Once initialized, the time counter will count down with

 

 

 

each peripheral clock until it reaches 0. A second interrupt cannot be generated until this

 

 

 

counter reaches 0. Any time the time counter has a non-zero value, the interrupt logic will

 

 

 

block the EMAC_MDIO_INT interrupt to the CPU. Thus, if any of the interrupts coming to the

 

 

 

EMAC control module is asserted, the interrupt logic will assert the EMAC_MDIO_INT signal

 

 

 

to the CPU, provided the INTEN bit in EWCTL is set, and the time counter value is 0.

54 Ethernet Media Access Controller (EMAC)/SPRU941A –April 2007

Management Data Input/Output (MDIO)

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Texas Instruments TMS320DM643X DMP manual Emac Control Module Interrupt Timer Count Register Ewinttcnt