Content

Raspberry Pi: Config.txt

During the booting process by the BCM2385 multimedia processor, an optional configuration file can also be read from the boot partition by the VideoCore Code for configuring the BCM2385 multimedia processor before the configuration options can be controlled by the ARM code.

The Format of Parameter Setting

One parameter option per line with the form "property=value" where value is an integer. And comment line begins with "#"

The Parameter Settings

• arm_freq : frequency of ARM in MHz. Default 700.
• gpu_freq : Sets core_freq, h264_freq, isp_freq, v3d_freq together.
  • core_freq : frequency of GPU processor core in MHz. Default 250.
  • h264_freq: frequency of hardware video block in MHz. Default 250.
  • isp_freq: frequency of image sensor pipeline block in MHz. Default 250.
  • v3d_freq: frequency of 3D block in MHz. Default 250.
• sdram_freq: frequency of SDRAM in MHz. Default 400.
• over_voltage_* settings: When the of of over_voltage_* settings is used, the OTP (one-time-programmable) bit will be blowed. Besides overclocking itself may only cause system unstable with little impact on the chip lifetime, however overvoltaging may have a significant impact on chip lifetime.
  • over_voltage: ARM/GPU core voltage adjust. [-16,8] equates to [0.8V,1.4V]. Default 0 (1.2V)
  • over_voltage_sdram: Sets over_voltage_sdram_c, over_voltage_sdram_i, over_voltage_sdram_p together
  • over_voltage_sdram_c: SDRAM controller voltage adjust. [-16,8] equates to [0.8V,1.4V]. Default 0 (1.2V)
  • over_voltage_sdram_i: SDRAM I/O voltage adjust. [-16,8] equates to [0.8V,1.4V]. Default 0 (1.2V)
  • over_voltage_sdram_p: SDRAM phy voltage adjust. [-16,8] equates to [0.8V,1.4V]. Default 0 (1.2V)
• sdtv_mode: composite tv mode. Default is 0 (NTSC)
  • SDTV_MODE_NTSC = 0, /**<Normal NTSC */
  • SDTV_MODE_NTSC_J = 1, /**<Japanese version of NTSC - no pedestal.*/
  • SDTV_MODE_PAL = 2, /**<Normal PAL */
  • SDTV_MODE_PAL_M = 3, /**<Brazilian version of PAL - 525/60 rather than 625/50, different subcarrier */
• sdtv_aspect: composite aspect ratio. Default is 1 (4:3)
  • SDTV_ASPECT_4_3 = 1, /**<4:3 */
  • SDTV_ASPECT_14_9 = 2, /**<14:9 */
  • SDTV_ASPECT_16_9 = 3 /**<16:9 */
• hdmi_mode: hdmi mode. Default is negotiated with display.
  • HDMI_CEA_VGA = 1,
  • HDMI_CEA_480p60 = 2,
  • HDMI_CEA_480p60H = 3,
  • HDMI_CEA_720p60 = 4,
  • HDMI_CEA_1080i60 = 5,
  • HDMI_CEA_480i60 = 6,
  • HDMI_CEA_480i60H = 7,
  • HDMI_CEA_240p60 = 8,
  • HDMI_CEA_240p60H = 9,
  • HDMI_CEA_480i60_4x = 10,
  • HDMI_CEA_480i60_4xH = 11,
  • HDMI_CEA_240p60_4x = 12,
  • HDMI_CEA_240p60_4xH = 13,
  • HDMI_CEA_480p60_2x = 14,
  • HDMI_CEA_480p60_2xH = 15,
  • HDMI_CEA_1080p60 = 16,
  • HDMI_CEA_576p50 = 17,
  • HDMI_CEA_576p50H = 18,
  • HDMI_CEA_720p50 = 19,
  • HDMI_CEA_1080i50 = 20,
  • HDMI_CEA_576i50 = 21,
  • HDMI_CEA_576i50H = 22,
  • HDMI_CEA_288p50 = 23,
  • HDMI_CEA_288p50H = 24,
  • HDMI_CEA_576i50_4x = 25,
  • HDMI_CEA_576i50_4xH = 26,
  • HDMI_CEA_288p50_4x = 27,
  • HDMI_CEA_288p50_4xH = 28,
  • HDMI_CEA_576p50_2x = 29,
  • HDMI_CEA_576p50_2xH = 30,
  • HDMI_CEA_1080p50 = 31,
  • HDMI_CEA_1080p24 = 32,
  • HDMI_CEA_1080p25 = 33,
  • HDMI_CEA_1080p30 = 34,
  • HDMI_CEA_480p60_4x = 35,
  • HDMI_CEA_480p60_4xH = 36,
  • HDMI_CEA_576p50_4x = 37,
  • HDMI_CEA_576p50_4xH = 38,
  • HDMI_CEA_1080i50_rb = 39,
  • HDMI_CEA_1080i100 = 40,
  • HDMI_CEA_720p100 = 41,
  • HDMI_CEA_576p100 = 42,
  • HDMI_CEA_576p100H = 43,
  • HDMI_CEA_576i100 = 44,
  • HDMI_CEA_576i100H = 45,
  • HDMI_CEA_1080i120 = 46,
  • HDMI_CEA_720p120 = 47,
  • HDMI_CEA_480p120 = 48,
  • HDMI_CEA_480p120H = 49,
  • HDMI_CEA_480i120 = 50,
  • HDMI_CEA_480i120H = 51,
  • HDMI_CEA_576p200 = 52,
  • HDMI_CEA_576p200H = 53,
  • HDMI_CEA_576i200 = 54,
  • HDMI_CEA_576i200H = 55,
  • HDMI_CEA_480p240 = 56,
  • HDMI_CEA_480p240H = 57,
  • HDMI_CEA_480i240 = 58,
  • HDMI_CEA_480i240H = 59,
• overscan_left: number of pixels to skip on left
• overscan_right: number of pixels to skip on right
• overscan_top: number of pixels to skip on top
• overscan_bottom: number of pixels to skip on bottom
• framebuffer_width: console framebuffer width in pixels. Default matches display.
• framebuffer_height: console framebuffer height in pixels. Default matches display.
• test_mode: enable test sound/image during boot for manufacturing test.
• enable_l2cache: enable ARM access to GPU's L2 cache. Needs corresponding L2 enabled kernel. Default 0.
  • Note: The L2 cache is a 128k 4 way set associative cache. The L2 cache is dedicated to the GPU only by default and is bypassed by the ARM processor. The L2 cache is part of the GPU design. The clock cycle of L2 cache may closer to the clock cyle of GPU as the GPU and ARM are clocked at different clock cycles. Besides, the L2 cache is also outside the ARM's MMU.