
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 5: The Clock Module
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
5-15
2.5 Power-up and Reset sequence
On power-up, the Clock module outputs the default 27 MHz clocks to all the PNX15xx
Series modules. Once the Reset module has released the internal module resets, the
boot-up sequence executed by the Boot module starts off the 27 MHz clock. At some
point in the boot up sequence, the Boot module switches TM3260 and the DDR
clocks to the associated PLLs, PLL0 and PLL2. The Clock module keeps feeding the
other PNX15xx Series modules with the initial 27 MHz clock until the software
decides otherwise.
2.6 Clock Stretching
The TM3260 clock, clk_tm, can be paused or stretched for one clock pulse. A counter
counts to a pre-programmed value. When this value is reached the clock gating circuit
will turn off the TM3260 clock for one clock period. Then the TM3260 clock is turned
back on.
The procedure to operate the clock stretching circuit is to program the
CLK_STRETCHER_CTL MMIO register to the value desired between clock
stretches. For example a value of 3 turns off the clock every 3 clocks as pictured in
A Write to the CLK_STRETCHER_CTL register acts as the enable for the feature.
clk_qvcp
CLK_QVCP_OUT_CTL
XIO_ACK
clk_qvcp_pix
CLK_QVCP_PIX_CTL
XIO_D[8]
clk_qvcp_proc
CLK_QVCP_PROC_CTL
XIO_D[9]
clk_lcd_tstamp
CLK_LCD_TSTAMP_CTL
XIO_D[10]
clk_vip
CLK_VIP_CTL
XIO_D[11]
clk_vld
CLK_VLD_CTL
XIO_D[12]
ai_osclk
AI_OSCLK_CTL
XIO_D[13]
ao_osclk
AO_OSCLK_CTL
XIO_D[14]
clk_spdo
CLK_SPDO_CTL
XIO_D[15]
clk_spdi
CLK_SPDI_CTL
LAN_TXD[0]
clk_gpio_q4
CLK_GPIO_Q4_CTL
LAN_TXD[1]
clk_gpio_q5
CLK_GPIO_Q5_CTL
LAN_TXD[2]
clk_gpio_q6_12
CLK_GPIO_Q6_12_CTL
LAN_TXD[3]
clk_gpio_13
CLK_GPIO_13_CTL
LAN_RXD[0]
clk_gpio_14
CLK_GPIO_14_CTL
LAN_RXD[1]
clk_fgpo
CLK_FGPO_CTL
LAN_RXD[2]
clk_fgpi
CLK_FGPI_CTL
LAN_RXD[3]
Table 8: Bypass Clock Sources
Clocks from Clock
Module
Bypass Control Register
GPIO pin
Assignment