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IPegStabilityModule

Volt Protocol

Fei Peg Stability Module

The Fei PSM is a contract which holds a reserve of assets in order to exchange FEI at $1 of underlying assets with a fee. mint() - buy FEI for $1 of underlying tokens redeem() - sell FEI back for $1 of the same The contract has a reservesThreshold() of underlying meant to stand ready for redemptions. Any surplus reserves can be sent into the PCV using allocateSurplus() The contract is a PCVDeposit - to track reserves OracleRef - to determine price of underlying, and RateLimitedMinter - to stop infinite mints and related issues (but this is in the implementation due to inheritance-linearization difficulties) Inspired by MakerDAO PSM, code written without reference

Methods​

MAX_FEE​

function MAX_FEE() external view returns (uint256)

the max mint and redeem fee in basis points

Returns​

NameTypeDescription
_0uint256undefined

allocateSurplus​

function allocateSurplus() external nonpayable

send any surplus reserves to the PCV allocation

getMaxMintAmountOut​

function getMaxMintAmountOut() external view returns (uint256)

the maximum mint amount out

Returns​

NameTypeDescription
_0uint256undefined

getMintAmountOut​

function getMintAmountOut(uint256 amountIn) external view returns (uint256 amountFeiOut)

calculate the amount of FEI out for a given amountIn of underlying

Parameters​

NameTypeDescription
amountInuint256undefined

Returns​

NameTypeDescription
amountFeiOutuint256undefined

getRedeemAmountOut​

function getRedeemAmountOut(uint256 amountFeiIn) external view returns (uint256 amountOut)

calculate the amount of underlying out for a given amountFeiIn of FEI

Parameters​

NameTypeDescription
amountFeiInuint256undefined

Returns​

NameTypeDescription
amountOutuint256undefined

hasSurplus​

function hasSurplus() external view returns (bool)

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

Returns​

NameTypeDescription
_0boolundefined

mint​

function mint(address to, uint256 amountIn, uint256 minAmountOut) external nonpayable returns (uint256 amountFeiOut)

mint amountFeiOut FEI to address to for amountIn underlying tokens

see getMintAmountOut() to pre-calculate amount out

Parameters​

NameTypeDescription
toaddressundefined
amountInuint256undefined
minAmountOutuint256undefined

Returns​

NameTypeDescription
amountFeiOutuint256undefined

mintFeeBasisPoints​

function mintFeeBasisPoints() external view returns (uint256)

the mint fee vs oracle price in basis point terms

Returns​

NameTypeDescription
_0uint256undefined

redeem​

function redeem(address to, uint256 amountFeiIn, uint256 minAmountOut) external nonpayable returns (uint256 amountOut)

redeem amountFeiIn FEI for amountOut underlying tokens and send to address to

see getRedeemAmountOut() to pre-calculate amount out

Parameters​

NameTypeDescription
toaddressundefined
amountFeiInuint256undefined
minAmountOutuint256undefined

Returns​

NameTypeDescription
amountOutuint256undefined

redeemFeeBasisPoints​

function redeemFeeBasisPoints() external view returns (uint256)

the redemption fee vs oracle price in basis point terms

Returns​

NameTypeDescription
_0uint256undefined

reservesSurplus​

function reservesSurplus() external view returns (int256)

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

Returns​

NameTypeDescription
_0int256undefined

reservesThreshold​

function reservesThreshold() external view returns (uint256)

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

Returns​

NameTypeDescription
_0uint256undefined

setMintFee​

function setMintFee(uint256 newMintFeeBasisPoints) external nonpayable

set the mint fee vs oracle price in basis point terms

Parameters​

NameTypeDescription
newMintFeeBasisPointsuint256undefined

setRedeemFee​

function setRedeemFee(uint256 newRedeemFeeBasisPoints) external nonpayable

set the redemption fee vs oracle price in basis point terms

Parameters​

NameTypeDescription
newRedeemFeeBasisPointsuint256undefined

setReservesThreshold​

function setReservesThreshold(uint256 newReservesThreshold) external nonpayable

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

Parameters​

NameTypeDescription
newReservesThresholduint256undefined

setSurplusTarget​

function setSurplusTarget(contract IPCVDeposit newTarget) external nonpayable

set the target for sending surplus reserves

Parameters​

NameTypeDescription
newTargetcontract IPCVDepositundefined

surplusTarget​

function surplusTarget() external view returns (contract IPCVDeposit)

the PCV deposit target to send surplus reserves

Returns​

NameTypeDescription
_0contract IPCVDepositundefined

underlyingToken​

function underlyingToken() external view returns (contract IERC20)

the underlying token exchanged for FEI

Returns​

NameTypeDescription
_0contract IERC20undefined

Events​

AllocateSurplus​

event AllocateSurplus(address indexed caller, uint256 amount)

event emitted when excess PCV is allocated

Parameters​

NameTypeDescription
caller indexedaddressundefined
amountuint256undefined

MaxFeeUpdate​

event MaxFeeUpdate(uint256 oldMaxFee, uint256 newMaxFee)

event emitted when a new max fee is set

Parameters​

NameTypeDescription
oldMaxFeeuint256undefined
newMaxFeeuint256undefined

Mint​

event Mint(address to, uint256 amountIn, uint256 amountFeiOut)

event emitted when fei gets minted

Parameters​

NameTypeDescription
toaddressundefined
amountInuint256undefined
amountFeiOutuint256undefined

MintFeeUpdate​

event MintFeeUpdate(uint256 oldMintFee, uint256 newMintFee)

event emitted when a new mint fee is set

Parameters​

NameTypeDescription
oldMintFeeuint256undefined
newMintFeeuint256undefined

Redeem​

event Redeem(address to, uint256 amountFeiIn, uint256 amountAssetOut)

event emitted upon a redemption

Parameters​

NameTypeDescription
toaddressundefined
amountFeiInuint256undefined
amountAssetOutuint256undefined

RedeemFeeUpdate​

event RedeemFeeUpdate(uint256 oldRedeemFee, uint256 newRedeemFee)

event emitted when a new redeem fee is set

Parameters​

NameTypeDescription
oldRedeemFeeuint256undefined
newRedeemFeeuint256undefined

ReservesThresholdUpdate​

event ReservesThresholdUpdate(uint256 oldReservesThreshold, uint256 newReservesThreshold)

event emitted when reservesThreshold is updated

Parameters​

NameTypeDescription
oldReservesThresholduint256undefined
newReservesThresholduint256undefined

SurplusTargetUpdate​

event SurplusTargetUpdate(contract IPCVDeposit oldTarget, contract IPCVDeposit newTarget)

event emitted when surplus target is updated

Parameters​

NameTypeDescription
oldTargetcontract IPCVDepositundefined
newTargetcontract IPCVDepositundefined