> For the complete documentation index, see [llms.txt](https://docs.essencefinance.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.essencefinance.io/development/smart-contracts/peg/pegstabilitymodule.md).

# PegStabilityModule

## Functions

### constructor

```solidity
function constructor(
    struct PegStabilityModule.OracleParams params,
    uint256 _mintFeeBasisPoints,
    uint256 _redeemFeeBasisPoints,
    uint256 _reservesThreshold,
    uint256 _chiLimitPerSecond,
    uint256 _mintingBufferCap,
    contract IERC20 _underlyingToken,
    contract IPCVDeposit _surplusTarget
) public
```

constructor

#### Parameters

| Name                    | Type                                   | Description                      |
| ----------------------- | -------------------------------------- | -------------------------------- |
| `params`                | struct PegStabilityModule.OracleParams | PSM constructor parameter struct |
| `_mintFeeBasisPoints`   | uint256                                |                                  |
| `_redeemFeeBasisPoints` | uint256                                |                                  |
| `_reservesThreshold`    | uint256                                |                                  |
| `_chiLimitPerSecond`    | uint256                                |                                  |
| `_mintingBufferCap`     | uint256                                |                                  |
| `_underlyingToken`      | contract IERC20                        |                                  |
| `_surplusTarget`        | contract IPCVDeposit                   |                                  |

### pauseRedeem

```solidity
function pauseRedeem() external
```

set secondary pausable methods to paused

### unpauseRedeem

```solidity
function unpauseRedeem() external
```

set secondary pausable methods to unpaused

### pauseMint

```solidity
function pauseMint() external
```

set secondary pausable methods to paused

### unpauseMint

```solidity
function unpauseMint() external
```

set secondary pausable methods to unpaused

### withdraw

```solidity
function withdraw(
    address to,
    uint256 amount
) external
```

withdraw assets from PSM to an external address

#### Parameters

| Name     | Type    | Description |
| -------- | ------- | ----------- |
| `to`     | address |             |
| `amount` | uint256 |             |

### setMintFee

```solidity
function setMintFee(
    uint256 newMintFeeBasisPoints
) external
```

set the mint fee vs oracle price in basis point terms

#### Parameters

| Name                    | Type    | Description |
| ----------------------- | ------- | ----------- |
| `newMintFeeBasisPoints` | uint256 |             |

### setRedeemFee

```solidity
function setRedeemFee(
    uint256 newRedeemFeeBasisPoints
) external
```

set the redemption fee vs oracle price in basis point terms

#### Parameters

| Name                      | Type    | Description |
| ------------------------- | ------- | ----------- |
| `newRedeemFeeBasisPoints` | uint256 |             |

### setReservesThreshold

```solidity
function setReservesThreshold(
    uint256 newReservesThreshold
) external
```

set the ideal amount of reserves for the contract to hold for redemptions

#### Parameters

| Name                   | Type    | Description |
| ---------------------- | ------- | ----------- |
| `newReservesThreshold` | uint256 |             |

### setSurplusTarget

```solidity
function setSurplusTarget(
    contract IPCVDeposit newTarget
) external
```

set the target for sending surplus reserves

#### Parameters

| Name        | Type                 | Description |
| ----------- | -------------------- | ----------- |
| `newTarget` | contract IPCVDeposit |             |

### \_setMintFee

```solidity
function _setMintFee(
    uint256 newMintFeeBasisPoints
) internal
```

set the mint fee vs oracle price in basis point terms

#### Parameters

| Name                    | Type    | Description |
| ----------------------- | ------- | ----------- |
| `newMintFeeBasisPoints` | uint256 |             |

### \_setRedeemFee

```solidity
function _setRedeemFee(
    uint256 newRedeemFeeBasisPoints
) internal
```

internal helper function to set the redemption fee

#### Parameters

| Name                      | Type    | Description |
| ------------------------- | ------- | ----------- |
| `newRedeemFeeBasisPoints` | uint256 |             |

### \_setReservesThreshold

```solidity
function _setReservesThreshold(
    uint256 newReservesThreshold
) internal
```

helper function to set reserves threshold

#### Parameters

| Name                   | Type    | Description |
| ---------------------- | ------- | ----------- |
| `newReservesThreshold` | uint256 |             |

### \_setSurplusTarget

```solidity
function _setSurplusTarget(
    contract IPCVDeposit newSurplusTarget
) internal
```

helper function to set the surplus target

#### Parameters

| Name               | Type                 | Description |
| ------------------ | -------------------- | ----------- |
| `newSurplusTarget` | contract IPCVDeposit |             |

### allocateSurplus

```solidity
function allocateSurplus() external
```

send any surplus reserves to the PCV allocation

### deposit

```solidity
function deposit() external
```

function to receive ERC20 tokens from external contracts

### \_redeem

```solidity
function _redeem(
    address to,
    uint256 amountChiIn,
    uint256 minAmountOut
) internal returns (uint256 amountOut)
```

internal helper method to redeem chi in exchange for an external asset

#### Parameters

| Name           | Type    | Description |
| -------------- | ------- | ----------- |
| `to`           | address |             |
| `amountChiIn`  | uint256 |             |
| `minAmountOut` | uint256 |             |

### \_mint

```solidity
function _mint(
    address to,
    uint256 amountIn,
    uint256 minAmountOut
) internal returns (uint256 amountChiOut)
```

internal helper method to mint chi in exchange for an external asset

#### Parameters

| Name           | Type    | Description |
| -------------- | ------- | ----------- |
| `to`           | address |             |
| `amountIn`     | uint256 |             |
| `minAmountOut` | uint256 |             |

### redeem

```solidity
function redeem(
    address to,
    uint256 amountChiIn,
    uint256 minAmountOut
) external returns (uint256 amountOut)
```

function to redeem CHI for an underlying asset We do not burn Chi; this allows the contract's balance of Chi to be used before the buffer is used In practice, this helps prevent artificial cycling of mint-burn cycles and prevents a griefing vector.

#### Parameters

| Name           | Type    | Description |
| -------------- | ------- | ----------- |
| `to`           | address |             |
| `amountChiIn`  | uint256 |             |
| `minAmountOut` | uint256 |             |

### mint

```solidity
function mint(
    address to,
    uint256 amountIn,
    uint256 minAmountOut
) external returns (uint256 amountChiOut)
```

function to buy CHI for an underlying asset We first transfer any contract-owned chi, then mint the remaining if necessary

#### Parameters

| Name           | Type    | Description |
| -------------- | ------- | ----------- |
| `to`           | address |             |
| `amountIn`     | uint256 |             |
| `minAmountOut` | uint256 |             |

### getMintAmountOut

```solidity
function getMintAmountOut(
    uint256 amountIn
) public returns (uint256 amountChiOut)
```

calculate the amount of CHI out for a given `amountIn` of underlying First get oracle price of token Then figure out how many dollars that amount in is worth by multiplying price \* amount. ensure decimals are normalized if on underlying they are not 18

#### Parameters

| Name       | Type    | Description |
| ---------- | ------- | ----------- |
| `amountIn` | uint256 |             |

### getRedeemAmountOut

```solidity
function getRedeemAmountOut(
    uint256 amountChiIn
) public returns (uint256 amountTokenOut)
```

calculate the amount of underlying out for a given `amountChiIn` of CHI First get oracle price of token Then figure out how many dollars that amount in is worth by multiplying price \* amount. ensure decimals are normalized if on underlying they are not 18

#### Parameters

| Name          | Type    | Description |
| ------------- | ------- | ----------- |
| `amountChiIn` | uint256 |             |

### getMaxMintAmountOut

```solidity
function getMaxMintAmountOut() external returns (uint256)
```

the maximum mint amount out

### hasSurplus

```solidity
function hasSurplus() external returns (bool)
```

a flag for whether the current balance is above (true) or below (false) the reservesThreshold

### reservesSurplus

```solidity
function reservesSurplus() public returns (int256)
```

an integer representing the positive surplus or negative deficit of contract balance vs reservesThreshold

### balance

```solidity
function balance() public returns (uint256)
```

function from PCVDeposit that must be overriden

### balanceReportedIn

```solidity
function balanceReportedIn() external returns (address)
```

returns address of token this contracts balance is reported in

### resistantBalanceAndChi

```solidity
function resistantBalanceAndChi() public returns (uint256, uint256)
```

override default behavior of not checking chi balance

### \_getMintAmountOut

```solidity
function _getMintAmountOut(
    uint256 amountIn
) internal returns (uint256 amountChiOut)
```

helper function to get mint amount out based on current market prices

will revert if price is outside of bounds and bounded PSM is being used

#### Parameters

| Name       | Type    | Description |
| ---------- | ------- | ----------- |
| `amountIn` | uint256 |             |

### \_getRedeemAmountOut

```solidity
function _getRedeemAmountOut(
    uint256 amountChiIn
) internal returns (uint256 amountTokenOut)
```

helper function to get redeem amount out based on current market prices

will revert if price is outside of bounds and bounded PSM is being used

#### Parameters

| Name          | Type    | Description |
| ------------- | ------- | ----------- |
| `amountChiIn` | uint256 |             |

### \_allocate

```solidity
function _allocate(
    uint256 amount
) internal
```

Allocates a portion of escrowed PCV to a target PCV deposit

#### Parameters

| Name     | Type    | Description |
| -------- | ------- | ----------- |
| `amount` | uint256 |             |

### \_transfer

```solidity
function _transfer(
    address to,
    uint256 amount
) internal
```

transfer ERC20 token

#### Parameters

| Name     | Type    | Description |
| -------- | ------- | ----------- |
| `to`     | address |             |
| `amount` | uint256 |             |

### \_transferFrom

```solidity
function _transferFrom(
    address from,
    address to,
    uint256 amount
) internal
```

transfer assets from user to this contract

#### Parameters

| Name     | Type    | Description |
| -------- | ------- | ----------- |
| `from`   | address |             |
| `to`     | address |             |
| `amount` | uint256 |             |

### \_mintChi

```solidity
function _mintChi(
    address to,
    uint256 amount
) internal
```

mint amount of CHI to the specified user on a rate limit

#### Parameters

| Name     | Type    | Description |
| -------- | ------- | ----------- |
| `to`     | address |             |
| `amount` | uint256 |             |

### \_validatePriceRange

```solidity
function _validatePriceRange(
    struct Decimal.D256 price
) internal
```

overriden function in the bounded PSM

#### Parameters

| Name    | Type                | Description |
| ------- | ------------------- | ----------- |
| `price` | struct Decimal.D256 |             |

## Events

### RedemptionsPaused

```solidity
event RedemptionsPaused(
    address account
)
```

event that is emitted when redemptions are paused

#### Parameters

| Name                    | Type    | Description |
| ----------------------- | ------- | ----------- |
| `account`               | address |             |
| ### RedemptionsUnpaused |         |             |

```solidity
event RedemptionsUnpaused(
    address account
)
```

event that is emitted when redemptions are unpaused

#### Parameters

| Name              | Type    | Description |
| ----------------- | ------- | ----------- |
| `account`         | address |             |
| ### MintingPaused |         |             |

```solidity
event MintingPaused(
    address account
)
```

event that is emitted when minting is paused

#### Parameters

| Name                | Type    | Description |
| ------------------- | ------- | ----------- |
| `account`           | address |             |
| ### MintingUnpaused |         |             |

```solidity
event MintingUnpaused(
    address account
)
```

event that is emitted when minting is unpaused

#### Parameters

| Name      | Type    | Description |
| --------- | ------- | ----------- |
| `account` | address |             |


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