i.MX25 Features
This page outlines the Freescale i.MX25 features available as part of the Topaz CPU Module. It includes features that are available via external pins on the Topaz, and does not detail internal functions such as memory controllers, internal timers etc. Please note also that not all features listed may be supported by your chosen operating system.
Each section includes:
A brief overview of the feature along with any specific Topaz implementation notes.
List of features available on this interface.
List of external signals used with the interface. These signals are likely to be multiplexed with other signals. The following chapter details each external signal on the Topaz CPU Module along with the i.MX25 functions available on each pad.
For a full description of capabilities and details of registers, please refer to the Freescale i.MX25 Reference Manual.
Where you see Pad/Pin in the following tables, this refers to:
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LCD Controller
Overview
The i.MX5 LCD controller supports a wide variety of panels with resolutions up to 800x600, and the Topaz Module includes all the signals to support these panels.
In addition to standard panels, the i.MX25 also includes a Smart LCD Controller. This controller communicates with panels that have on-board memory.
The i.MX25 supports up to 24-bit displays; however, we recommend running Topaz in 16-bit mode for performance reasons. In 16-bit mode, the signals to use are:
Red: LD17(MSB) – LD13(LSB)
Green: LD11 (MSB) – LD6 (LSB)
Blue: LD5 (MSB) – LD1 (LSB)
Note that LD16 and LD17 are likely to be 1.8V signals and will need to be converted to 3.3V in order for most LCDs to function correctly.
Features
Maximum screen resolution of 800x600
Support for single-screen (non-split) monochrome or color LCD panels, and for self-refresh type LCD panels
For 4- and 8-bpp color, a palette table is used for remapping of data from memory, independent of the type of panel used. For 1, 2, 12, 16, 18, and 24 bpp, the palette table is bypassed.
Supports timing requirements for Sharp 240 × 320 HR-TFT panel
Hardware-generated cursor with blink, color, and size programmability
Logical operation between color hardware cursor and background
Hardware panning (soft horizontal scrolling)
8-bit pulse width modulator for software contrast control
Graphic window support for viewfinder function in color display
Graphic window color keying for graphical hardware cursor
256 transparency levels for alpha blending between graphic window and background plane
Signals
The following signals are used by the standard LCD controller.
Pad/Pin | Voltage | Signal Name | Description | Notes |
E2/50 | 3.3V | CONTRAST | Contrast output |
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L1/25 | 3.3V | LD0 | Data signal |
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L2/26 | 3.3V | LD1 | Data signal |
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L3/27 | 3.3V | LD2 | Data signal |
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K1/28 | 3.3V | LD3 | Data signal |
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K2/29 | 3.3V | LD4 | Data signal |
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K3/30 | 3.3V | LD5 | Data signal |
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J1/31 | 3.3V | LD6 | Data signal |
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J2/32 | 3.3V | LD7 | Data signal |
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J3/33 | 3.3V | LD8 | Data signal |
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H1/34 | 3.3V | LD9 | Data signal |
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H2/35 | 3.3V | LD10 | Data signal |
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H3/36 | 3.3V | LD11 | Data signal |
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G1/37 | 3.3V | LD12 | Data signal |
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G2/38 | 3.3V | LD13 | Data signal |
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G3/39 | 3.3V | LD14 | Data signal |
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F1/40 | 3.3V | LD15 | Data signal |
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F2/49 | 3.3V | LSCLK | Pixel Clock |
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F3/51 | 3.3V | OE_ACD | Output enable |
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K4/53 | 3.3V | VSYNC | Vertical Sync |
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L4/52 | 3.3V | HSYNC | Horizontal Sync |
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U1/164 | 3.3V | LD16 | Data Signal | Also on B3 (3.3V) and A12 (1.8V) |
Y8/165 | 3.3V | LD17 | Data Signal | Also on A11 (1.8V) |
A13/193 | 1.8V | LD18 | Data Signal | Voltage level converter required |
A14/194 | 1.8V | LD19 | Data Signal | Voltage level converter required |
A15/195 | 1.8V | LD20 | Data Signal | Voltage level converter required |
A16/196 | 1.8V | LD21 | Data Signal | Voltage level converter required |
F16/197 | 1.8V | LD22 | Data Signal | Voltage level converter required |
F15/198 | 1.8V | LD23 | Data Signal | Voltage level converter required |
C1/8 | 3.3V | CLS | Special timing signal for Sharp TFT |
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C2/9 | 3.3V | SPL | Special timing signal for Sharp TFT |
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D2/10 | 3.3V | PS | Special timing signal for Sharp TFT |
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D1/11 | 3.3V | REV | Special timing signal for Sharp TFT |
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The following signals are used by the Smart LCD controller (SLCD)
Pad/Pin | Voltage | Signal Name | Description | Notes |
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E2/50 | 3.3V | CONTRAST | Contrast output |
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L1/25 | 3.3V | DATA_0 | Data signal |
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L2/26 | 3.3V | DATA_1 | Data signal |
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L3/27 | 3.3V | DATA_2 | Data signal |
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K1/28 | 3.3V | DATA_3 | Data signal |
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K2/29 | 3.3V | DATA_4 | Data signal |
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K3/30 | 3.3V | DATA_5 | Data signal |
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J1/31 | 3.3V | DATA_6 | Data signal |
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J2/32 | 3.3V | DATA_7 | Data signal |
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J3/33 | 3.3V | DATA_8 | Data signal |
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H1/34 | 3.3V | DATA_9 | Data signal |
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H2/35 | 3.3V | DATA_10 | Data signal |
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H3/36 | 3.3V | DATA_11 | Data signal |
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G1/37 | 3.3V | DATA_12 | Data signal |
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G2/38 | 3.3V | DATA_13 | Data signal |
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G3/39 | 3.3V | DATA_14 | Data signal |
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F1/40 | 3.3V | DATA_15 | Data signal |
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F2/49 | 3.3V | LCD_CS | Used as a chip select for external display controller in serial mode. In parallel mode, used as write strobe for the external display controller. This signal polarity is programmable. |
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F3/51 | 3.3V | LCD_RS | LCD Register Select signal that indicates to the LCD device whether data being written is display data or control data. This signal polarity is programmable. |
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Touch Screen Controller (TSC) and Analog-to-Digital Converter (ADC)
Overview
The i.MX25 includes an on-board controller for 4- or 5-wire resistive touch screens, along with 3 additional general-purpose ADC channels. The touch screen inputs may be used as general-purpose inputs if the touch screen controller is not used.
4-wire touch screens are most common; however, 5-wire screens are more robust and support larger displays (up to 22").
Features
Integrated 12-bit, 125-kHz ADC
Supports ratiometric measurement drivers
Configurable in single-ended or differential (ratiometric) topologies
Configurable to built-in voltage reference generator or external reference voltage
Supports 4- and 5-wire touch screens with 5 input channels for touch screen measurements (x+, x-, y+, y-, w)
Supports general-purpose analog measurements (such as temperature and voltage) with 3 input channels (aux0, aux1, aux2), or 8 input channels if touch interface is not used
Two independent measurement queues: TCQ for touch screen and GCQ for general-purpose measurements
Two independent FIFOs, each with 16 entries×16 bits, for storing TCQ and GCQ conversion results