Direct Drive LCD Design Guide

Figure 5 H8SX SDRAM in Cluster Mode

Note 1: To create the highest LCD Dot Clock frequency on the H8SX requires using cluster mode. In this mode, EDACK is not generated and an equivalent signal must be generated. The above circuit creates the necessary timing.

2.4 Driver Mode Configuration

The driver characteristics are configured with the following macros.

2.4.1DOT_CLOCK_FREQUENCY_DATA

This macro configures the dot clock frequency during the data transfer portion of the LCD update cycle. This value must be achievable by the configured BCLK_FREQUENCY and RAM configuration. This value is checked against other system parameters and an error will be generated if the value is not achievable.

2.4.2DOT_CLOCK_FREQUENCY_BLANK

This macro configures the dot clock frequency during the blanking portion of the LCD update cycle. This value must be achievable by the configured PCLK_FREQUENCY as it generated by the TPU. This value is checked against other system parameters and an error will be generated if the value is not achievable.

2.4.3DESIRED_FRAME_RATE

This macro configures the initial selection of LCD frame rate. The frame rate can also be modified at runtime via the LCDSetFrameRate API call. To achieve the desired frame rate, the vertical blanking time is extended beyond the values configured in the LCD panel configuration. This value is checked against other system parameters and an error will be generated if the value is not achievable.

2.4.4MINIMUM_MCU_ACCESS_PCT

This macro configures the user’s minimum acceptable percentage of time that the MCU core has access to the frame RAM (the MCU core only has access to the frame RAM during the vertical blanking time). This value interacts with DESIRED_FRAME_RATE macro…higher access percentage is achievable at lower frame rates (as the bus is less consumed with frame updates). This value is checked against other system parameters and an error will be generated if the value is not achievable.

2.5 LCD Panel Configuration

The LCD Direct Driver is configured to operate with a given LCD panel by setting macro definitions. These values are readily available in the data sheet for the selected panel.

2.5.1DOT_INVERT

This macro is used to control whether the RGB data is latched on the rising or the falling edge of the dot clock. If the macro is not defined, the data is latched on the rising edge, if it is defined, the data will be latched on the falling edge. Note that when using the multiplexed EDACK and TPU modes, the EDACK signal will also need to be inverted in hardware for falling edge operation (see section on dot clock hardware connections).

2.5.2V_LINES_xx and H_DOT_xx

Refer to the following diagram for definition of these values.

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Renesas H8SX user manual Driver Mode Configuration, LCD Panel Configuration, VLINESxx and HDOTxx
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H8S, H8SX specifications

Renesas H8S and H8SX microcontrollers are part of Renesas Electronics' H-series of 16-bit microcontrollers, widely known for their rich functionality, exceptional performance, and versatility in embedded applications. These microcontrollers are ideal for a variety of applications ranging from automotive systems to industrial automation and consumer electronics.

The key feature of the H8S series is its high-performance CPU architecture, which includes efficient instruction execution, allowing for faster processing of tasks. The H8S series operates at clock speeds typically up to 24 MHz, providing ample processing power for complex applications. The H8SX series builds upon the H8S foundation with enhanced performance capabilities, including advanced instruction sets and support for higher clock frequencies, which can reach up to 40 MHz.

One of the standout characteristics of the H8S and H8SX microcontrollers is their rich peripheral set. They offer multiple I/O ports, timers, ADCs (Analog-to-Digital Converters), and communication interfaces such as SPI, I2C, and UART. The built-in ADCs allow for accurate analog signal processing, making these microcontrollers suitable for measuring temperature, pressure, and other sensor inputs in real time.

Moreover, the H8SX series provides additional features like improved flash memory capacity, enabling more complex applications to be developed and more extensive firmware to be stored. With the integration of a high-performance interrupt controller, the H8SX models can manage multiple interrupt sources efficiently, allowing for real-time response to events.

The H8S and H8SX microcontrollers also support a variety of development environments and programming languages, making them accessible for developers with varying skill levels. They are compatible with both C and assembly language programming, along with a range of development tools and IDEs (Integrated Development Environments).

In terms of power consumption, these microcontrollers are designed to be energy-efficient, making them ideal for battery-operated devices. With features such as low-power modes that allow the device to enter sleep modes when inactive, the H8S and H8SX microcontrollers help extend the battery life of applications.

In summary, Renesas H8S and H8SX microcontrollers stand out due to their performance, extensive peripheral functionality, versatility, and energy efficiency. Their rich feature set and compatibility with a variety of development tools make them a desirable choice for developers looking to create innovative embedded solutions across multiple industries.
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