MPC555 Resource Configuration (Embedded Target for Motorola MPC555)

Support device configuration for MPC555 CPU and MIOS, QADC, and TouCAN Submodules

Library

Embedded Target for Motorola MPC555

Description

The MPC555 Resource Configuration block differs in function and behavior from conventional blocks. Therefore, we refer to this block as the MPC555 Resource Configuration object.

The MPC555 Resource Configuration object maintains configuration settings that apply to the MPC555 CPU and its MIOS, QADC, and TouCAN subsystems. Although the MPC555 Resource Configuration object resembles a conventional block in appearance, it is not connected to other blocks via input or output ports. This is because the purpose of the MPC555 Resource Configuration object is to provide information to other blocks in the model. MPC555 device driver blocks register their presence with the MPC555 Resource Configuration object when they are added to a model or subsystem; they can then query the MPC555 Resource Configuration object for required information.

To install a MPC555 Resource Configuration object in a model or subsystem, open the top-level Embedded Target for Motorola MPC555 library and select the MPC555 Resource Configuration icon. Then drag and drop it into your model or subsystem, like a conventional block.

Having installed a MPC555 Resource Configuration object into your model or subsystem, you can then select and edit configuration settings in the MPC555 Resource Configuration window. See Using the MPC555 Resource Configuration Window for further information.

Note Any model or subsystem using device driver blocks from the Embedded Target for Motorola MPC555 library must contain an MPC555 Resource Configuration object. You should place an MPC555 Resource Configuration object at the top level system for which you are going to generate code. If your whole model is going to run on the target processor, put the MPC555 Resource Configuration object at the root level of the model. If you are going to generate code from separate subsystems (to run specific subsystems on the target), place an MPC555 Resource Configuration object at the top level of each subsystem. You should not have more than one MPC555 Resource Configuration object in the same branch of the model hierarchy. Errors will result if these conditions are not met.

Types of Configurations

A configuration is a collection of parameter values affecting the operation of a group of device driver blocks in one of the Embedded Target for Motorola MPC555 libraries, such as the MIOS1, QADC64 or TouCAN libraries. The MPC555 Resource Configuration object currently supports the following types of configurations:

System Configuration: MPC555 clocks and other CPU-related parameters.
MIOS1 Configuration: parameters related to the Modular Input/Output System (MIOS).
QADC64 Configuration: parameters related to the Queued Analog-to-Digital Converter module (QADC).
TouCAN Configuration: parameters related to the CAN 2.0B Controller Module (TouCAN).

Active and Inactive Configurations

An active configuration is a configuration associated with blocks of the model or subsystem in which the MPC555 Resource Configuration object is installed. There is always an active MPC555 configuration. For any other configuration type (e.g., QADC, MIOS, or TouCAN), there is at most one active configuration.

Consider this model, which contains a MPC555 Resource Configuration object but no MPC555 device driver blocks.

This model has only one active configuration, for the MPC555 itself, as shown in the MPC555 Resource Configuration window.

When a device driver block is added to the model, an appropriate configuration is created and activated. This figure shows an MIOS Digital Out block added to the model.

The addition of the MIOS Digital Out block causes an MIOS configuration to be added to the list of active configurations, as shown in this figure.

A configuration remains active until all blocks associated with it are removed from the model or subsystem. At that point, the configuration is in an inactive state. Inactive configurations are not shown in the MPC555 Resource Configuration window. You can reactivate a configuration by simply adding an appropriate block into the model.

Note When using device driver blocks from the Embedded Target for Motorola MPC555 libraries in conjunction with the MPC555 Resource Configuration block, do not disable or break library links on the driver blocks. If library links are disabled or broken, the MPC555 Resource Configuration block will operate incorrectly.

When you save a model that contains inactive configurations, you have the option to either save inactive configurations with the model, or delete them.

Using the MPC555 Resource Configuration Window

To open the MPC555 Resource Configuration window, install a MPC555 Resource Configuration object in your model or subsystem, and double-click on the MPC555 Resource Configuration icon. The MPC555 Resource Configuration window then opens.

Figure 5-1: MPC555 Resource Configuration Window

Figure 5-1 shows the MPC555 Resource Configuration window for a model that has active configurations for MPC555, MIOS1, QADC, and TouCAN.

The MPC555 Resource Configuration window consists of the following elements:

Active Configurations panel: This panel displays a list of currently active configurations. To edit a configuration, click on its entry in the list. The parameters for the selected configuration then appear in the System configuration panel.

To link back to the library associated with an active configuration, right-click on its entry in the list. From the popup menu that appears, select Go to library.

To see documentation associated with an active configuration, right-click on its entry in the list. From the popup menu that appears, select Help.

System configuration panel: This panel lets you edit the parameters of the selected configuration. The parameters of each configuration type are detailed in MPC555 Resource Configuration Window Parameters.

Note There is no Apply or Undo functionality in the System configuration panel. All parameter changes are applied immediately.

Status panel: The Status panel displays error messages that may arise if resource allocation conflicts are detected in the configuration.
Validate Configuration button: After you edit a configuration, you should always click the Validate Configuration button to check for resource allocation conflicts. For example, if both TouCAN modules A and B are assigned to interrupt level IRQ 1, the Validate Configuration process will detect the conflict and display a warning in the Status panel.

Note that the Validate Configuration button does not validate the entire model; it only checks for resource allocation conflicts related to the selected configuration. To detect problems related to the model as a whole, select Update diagram (Ctrl+D) from the Simulink Edit menu.

Close button: Dismisses the window.

MPC555 Resource Configuration Window Parameters

The sections below describe the parameters for each type of configuration in the MPC555 Resource Configuration window. The default parameter settings are optimal for most purposes. If you want to change the settings, we suggest you read the sections of the MPC555 Users Manual referenced below. You can find this document at the following URL.
http://e-www.motorola.com.

System Configuration Parameters

RT_ONESTEP_IRQ_LEVEL: The rt_OneStep function is the basic execution driver of all programs generated by the Embedded Target for Motorola MPC555. rt_OneStep is installed as a timer interrupt service routine; it sequences calls to the model_step function. The RT_ONESTEP_IRQ_LEVEL parameter lets you associate rt_OneStep with any of the available IRQ levels (0..32). For non -interrupt driven operation, select Interrupts Disabled.; See the "Data Structures and Program Execution" section in the Real-Time Workshop Embedded Coder documentation for a detailed description of the rt_OneStep function.
System Clock Parameters: The other parameters in the MPC555 group alter the speed of three of the main clocks in the MPC555. Refer to section 8, "Clocks and Power Control," in the MPC555 Users Manual for information on these settings.

QADC64 Configuration Parameters

The QADC64 Configuration parameters configure the QADC64 operational mode and supports the blocks in the QADC sublibrary.

The QADC64 performs 10 bit analog to digital conversion on an input signal. Currently the blocks in this library support only the continuous scan mode of operation. In continuous scan mode, the QADC64 is set to run, and then continuously acquires data into its result buffer. Input is double buffered, so the model can read the result buffer at any time to get the latest available signal data.

The MPC555 has two QADC modules, QADC_A and QADC_B. You can program these individually. By default each QADC module has 16 input channels. By attaching an external multiplexer to three of the analog input pins, you can increase the number of possible channels to 41. These pins become outputs from the processor and can act as inputs to an analog multiplexer. The Multiplex Mode parameter determines whether the QADC64 operates in internally or externally multiplexed mode.

Refer to section 13, "Queued Analog-to-Digital Converter Module-64," in the MPC555 Users Manual for detailed information about the QADC64.

In general, you should not need to change any of the settings of the parameters described below from their defaults. The other parameters are advanced settings. Refer to section 13, "Queued Analog-to-Digital Converter Module-64," in the MPC555 Users Manual for information on these settings.

Multiplex Mode: Configures the QADC64 for internally or externally multiplexed mode by setting the MUX bit. The MUX bit determines the interpretation of the channel numbers and forces the MA[2:0] pins to be outputs. Valid settings are:

0 = Internally multiplexed : 16 possible channels
1 = Externally multiplexed : 41 possible channels

Prescaler Clock High Time: Prescaler clock high (PSH) time. The PSH field selects the QCLK high time in the prescaler. PSH value plus 1 represents the high time in IMB clocks.
Prescaler Clock Low Time: Prescaler clock low (PSL) time. The PSL field selects the QCLK low time in the prescaler. PSL value plus 1 represents the low time in IMB clocks.

MIOS1 Configuration Parameters

CounterClock: The MIOS counter clock is generated by the MIOS counter prescaler submodule. The MIOS counter clock drives the other MIOS1 submodules. The value shown for the counter clock is calculated automatically as the system clock frequency divided by the prescaler value.
Freeze Enable: This allows all counters on the MIOS1 to be frozen when the processor is stopped in debug mode. Note that this is in addition to the Freeze Enable setting for individual submodules on the MIOS1. To allow the counters on a particular submodule to be stopped, select Freeze enable here, and select Hold output when at debug break point (freeze enable) in the block parameters associated with the submodule (e.g., MIOS PWM block or MIOS Waveform Measurement block).
Modulus Counter 6 and 22: These two counters provide reference clocks to submodules such as the MIOS Pulse Width Modulation Submodule and the MIOS Double Action Submodule (Frequency / Period measurement) subsystems. If you change the Clock select to anything other than MMCSM Clock Prescaler, the MIOS Pulse Width Modulation and MIOS Waveform Measurement blocks will not work as expected. To change the clock frequency and hence the available resolution of pulse width modulation and waveform measurement, change the Clock Prescaler to a value between 0 and 255.; Refer to section 15.10, "MIOS Modulus Counter Submodule (MMCSM)," in the MPC555 Users Manual for information on these settings.

TouCAN Configuration Parameters

The parameters listed below are the same for TouCAN modules A and B. Consult Section 16 of the MPC555 User's Manual before editing the TouCAN configuration parameter defaults.

IRQ Level: The transmit queue for each TouCAN module requires a processor interrupt to run. Select an interrupt level (0-31) that is not used by any other device. Use the Validate Configuration button to make sure you do not select an interrupt level that is already in use.

Mask Configuration Parameters

Global RX Mask: Buffers 0-13 use this mask. Setting a bit to 1 in the mask causes the corresponding bits in the message to be masked out (i.e., ignored).
Mask RX 14: Same as Global RX Mask, but the mask applies only to buffer 14.
Mask RX 15: Same as Global RX Mask, but the mask applies only to buffer 15.
Mask Type: Specify whether the buffer masks are Standard or Extended frame IDs. If you want to receive Extended Frames in your model, you should set the Mask Type to Extended Message. The mask type option tells the compiler how to map the bits specified in the mask options to the bits in the hardware. The decision as to whether a message is a Standard or Extended frame is defined on a per message buffer basis.

Timing Configuration Parameters

CAN Bit Rate: Enter the desired bit rate. the default bit rate is 500000.0.
Number of Quanta: The number of TouCAN clock ticks per message bit.
Register Configuration: This field is read-only. It contains intermediate data used for bit-timing calculations.
Resynchronization Jump Width: The maximum number of clock ticks that the TouCAN device can resynchronize over when it detects that it is losing message synchronization.
Sample Point: The point in the message where the TouCAN tries to sample the value of the message bit.

Transmission Configuration Parameters

Transmit Buffer Number: Select one of buffers (0-15) for use as a transmit buffer. A queue is created for that buffer and is used by all TouCAN transmit blocks.
Transmit Queue Length: Length (in bytes) allocated to messages in the transmit queue.

MIOS Waveform Measurement QADC Analog In